About the blog: What Things Are Made Of


The United States relies on imports for dozens of commodities in everyday use. Often enough, that reliance is 100%. In this book I aim to provide awareness of the hidden geology and mineralogy behind common things, and to develop an appreciation for the global resource distribution that underpins our society. While concerns about oil import reliance are in the news every day, our needs for other minerals are comparable and are typically unknown even to technologically aware Americans.

Wednesday, July 27, 2011


Tourmaline from Madagascar
It’s been a while since I posted. Trip to Kansas, and my dog died, and June-July are absolutely the busiest time for tourism in Butte (I drive the Chamber of Commerce Trolley and lead historic walking tours in one of my other lives).

This post is for another country: Madagascar. Government edicts and other problems can dramatically impact mineral production and trade, and the coup in Madagascar in 2009, combined with the worldwide recession, certainly did not help the mineral industry there. Madagascar had been the world’s leading sapphire producer – but in 2008, the government banned export of rough gemstones. Why would they do that? Because of one specimen, the Heaven’s Gift Emerald. A 536-kg (1,182-pound) emerald in matrix, it was declared a national treasure worth $150 million; the government said its exportation was illegal, although courts ruled otherwise, and the ban on all exports was instituted and continued until mid-2009. By 2010 the gem industry was recovering – led in volume by tourmaline at 43,000 kg produced in Madagascar (compare 2,100 kg of sapphires).

Madagascar produces nearly 3% of the world’s titanium mineral concentrates (mostly ilmenite) but that ranks it #11. Australia and South Africa are the leaders, and the primary import sources for the US, which is 81% dependent on imports. The titanium dioxide pigment industry in the US is valued at about $3 billion, about the 7th most valuable mineral commodity in the US. Titanium dioxide finds its way into products from white sidewall tires to playing cards to Oreo cookies.

Cobalt, nickel, and increasing chromite mining are expected to improve Madagascar’s role in global mineral supplies in the next few years. Vanadium, uranium, and zircon mining may also impact the industry on the island as those reserves begin to be developed.

Photo: Tourmaline from Madagascar, credit: Laurie Minor-Penland (Smithsonian Institution), under CC by 2.0 license.

Friday, May 20, 2011

Everyone has an agenda

Everyone has an agenda. I do too, and because of my background as an oil explorationist it would be reasonable to think I might come down on the side of drilling, mining, and exploiting. Those things are important to modern life – but as a geologist, I also love the earth. I would call myself an environmentally sensitive resource explorer, even though some would say that’s an oxymoron.

In the introduction to What Things Are Made Of, I say the book is not intended to be a polemic against the mining industry – nor does it ignore the environmental consequences of mining. The point is that mined materials ARE used in incredible ways, and the book is a showcase for the necessity of mineral resources and the world's interdependence on their irregular distribution.

The National Mining Association promotes and lobbies for the mining industry. But they also have a great section, Minerals Make Life, whose message is essentially the same as mine: that everything takes minerals, that modern life would be impossible – not just inconvenient, but flat-out impossible – without them.

Sunday, May 8, 2011

What eyes are made of

As a geologist, I don’t get too much into biology (except for dead things – fossils). But given my early career analyzing kidney stones, I’ve been fascinated by biomineralization. So I was interested to learn of the first discovery of aragonite eyes.

Aragonite is the orthorhombic form of calcium carbonate, more familiar as calcite, the hexagonal (rhombohedral) type. Both are CaCO3 but their crystal structures are quite different. There is a rare less stable third form, vaterite, that crystallizes in the hexagonal dihexagonal dipyramidal crystal class and is sometimes found in gallstones. But back to eyes.

The research linked above found that some chiton lenses consist of aragonite crystals. Acanthopleura granulate, the fuzzy chiton of the West Indies, is a primitive mollusk, nonetheless pretty successful in evolutionary terms: the chiton group got its start in Devonian time about 400,000,000 years ago. The West Indies version lives in intertidal zones – so maybe it should be no surprise that aragonite crystallography allows the chiton to focus light equally well through both water and air.

Modern animal lenses are biochemical compounds—proteins—that have evolved transparency. But early in earth’s history, other critters, including trilobites, developed single crystals of calcite as optical lenses. This evolutionary development might have been an important factor in the Cambrian Explosion, the time about 530 million years ago when all the major phyla developed in a geologically very short time. In the Blink of an Eye, by Andrew Parker, explores this idea in depth.

In the industrial world, aragonite sometimes finds uses in glass and cement making, but calcite, far more common, is generally used. Aragonite and calcite both make beautiful collectible mineral specimens.

Chiton photo by Kirt L. Onthank, via Wikipedia under Creative Commons Attribution-Share Alike 3.0 Unported license.

Sunday, May 1, 2011

Why “Drill Baby Drill” doesn’t matter

Here’s why drilling in the US (or almost anywhere else) today won’t make any difference to the price of gasoline this year, next year, or even the year after that – no matter what politicians may say.

It takes a long, long time to find oil fields. It takes a long, long time to develop them. It takes a long, long time to finally get some oil out. The most recent large example I’ve seen is the Hebron field, offshore Newfoundland. Discovered in 1981, ExxonMobil and others are about to develop it. They expect “first oil” in 2017.

Hebron contains an estimated 700 million barrels. The estimated cost to set up the field for production is $C 8.3 billion (US$8.75 billion), and the estimated cost of operations over the life of the field is an additional $C 5.8 billion (US$6.11 billion). I have not found an estimate for finding costs specific to this field, so I’ll start with the estimated US offshore cost (average for 2006-2009) of US$53 per barrel. That would put finding at 53x700 million = $37 billion. That amortizes all exploration expenses including failures, to make an average total cost for actual oil found. But offshore Newfoundland has a relatively low finding cost – and Exxon is a pretty efficient company, so the actual finding cost for Hebron is probably closer to US$7 per barrel, or around $5 billion. So there’s something like just under US $20 billion in costs.

Production rate will be something like 150,000 barrels a day. At $100 a barrel, that’s a whopping $15,000,000 every day. And about 1300 days – under 4 years – to repay the investment. Of course, things like corporate taxes, transportation to market, and so on come out of that, as well as dividends to shareholders. And obviously it could not happen without the huge up-front expenditures. And the patience and money to wait 36 years from discovery to first oil.

36 years is an unusual length, even for offshore oil fields. But 10-15 years is not.

At 150,000 barrels a day, the 700,000,000 barrels would take about 4700 days or 13 years to produce. But it won’t be at 150,000 barrels a day for the entire time – it will ramp up to that point, probably be managed to sustain a production plateau, and then decline. For comparison, Prudhoe Bay, North America’s largest oil field, reached a peak production level of about 1.6 million barrels a day in 1979. It’s still producing, but about 200,000 barrels a day and declining. ExxonMobil estimates Hebron’s productive (economic) life at 46 years, beginning in 2017.

The main point of this exercise is to illustrate that any major oil field discovered today will not impact the price of oil until it is actually produced – in 10, 15, or 36 years from now. When you consider the future, consider that almost all existing oil wells are declining in their production rates, like those in Prudhoe Bay. 525,000 oil wells in the US average about 10 barrels per day per well, and the estimated rate of decline in US production ranges from 3% to 7% per year. If it is 5%, 5% of 10 barrels is half a barrel a year – so in 10 years, on average, the 525,000 wells in the US today will have lost 5 barrels per day per well, so they’d be at 5 barrels a day rather than 10. We’ll have lost 2.5 million barrels a day. You’d need almost 17 Hebron fields to make up that loss.

The Hebron field is an extreme example, but the concepts apply to any large oil discovery in the United States – and large oil discoveries in the United States are very few and far between, and getting scarcer. Drilling or discovery today will have no impact on the price of gasoline for years to come.

Tuesday, April 19, 2011

Could another Guano War develop?

A significant portion of Chapter 7 in What Things Are Made Of is devoted to phosphorus and phosphate rock, the building blocks of fertilizer and critical for life. The term “peak phosphorus” is only about four years old, but together with rare earths and lithium, global phosphorus supply is gaining mainstream attention.

While some research suggests phosphorus supplies could decline to problem levels by 2035, a recent analysis takes a different view. Either way, irregular distribution—one of the themes of my book—will probably impact phosphorus trade and use.

Phosphate rock ooids from Montana. Photo by Richard Gibson
In 2010, the U.S. imported 15% of its phosphate rock, the highest import dependency in history. The United States was a net exporter most years until about 1997, and imports were generally small until 2010, in part a reaction to the apparent ending of the global recession. All U.S. phosphate rock imports came from Morocco—the little country that owns or controls about three-quarters of the world’s reserves. Morocco and the U.S. produce about equal amounts, at 26 million tons per year (about 15% of world production each). China leads the world in phosphate rock mining with 37% of the total.

The mineral apatite, calcium phosphate, forms phosphate rock. Exactly how these deposits arise is still somewhat questionable, but upwelling ocean currents are thought to allow the chemical precipitation to occur. Other economic phosphate deposits are bird guano; islets off Peru covered with such material contributed to the “Guano War” in the 1860s. Whether demand for phosphate will lead to anything beyond trade wars remains to be seen.

Sunday, April 10, 2011

Dumpster Day

Saturday was Dumpster Day in Butte, Montana. It’s a day for recycling, sponsored by United Way, that comes every three months. And every three months the volume of stuff I generate appalls me. I alone threw away (well, saved for this day) four huge dog-food bags full of plastic, crushed to the extent possible, which is not much. Plastic dominates the piles I’ve been saving up, because paper, glass, steel, and aluminum are easier to take to the local recycling bins, which don’t accept plastic. All this plastic isn’t much by weight, but it sure is by volume.

Plastic is the hallmark of the Convenience Society. Easy to make, cheap, recyclable. It shows up in at least a dozen major sections of What Things Are Made Of. I get messages from people wanting to eliminate plastic as a way of saving oil. A nice idea, but not really valid. Plastic’s impact on the environment is a problem, but if we eliminated every bit of the plastic production in the US, it would be only a drop in the barrel of oil consumption.

One 42-gallon barrel of crude oil makes about 44 gallons of product, because during refining volumes increase. Of that final 44 gallons, 1.2 gallons make “feedstocks,” the chemical precursors to plastics, synthetic rubber, paints, petrochemicals, and more. That’s just under 3% of the products made from crude oil. Purists will add the energy cost to manufacture and distribute plastic products, which might get the total of oil consumption related to plastics up to 7%.

The point is that it’s just not that much volume. To conserve oil, forget plastic. A lot of it (such as grocery bags) is made from natural gas anyway, not oil. To conserve oil, drive less.

Wednesday, April 6, 2011

Bolivia: Lithium capital?

I hope my April Fool’s Day post didn’t bother anyone! Today I thought I’d focus on one country: Bolivia. Bolivia has been in the news as the world’s largest supply of lithium, and increasing demand for lithium batteries in electric vehicles might mean the US will have to cozy up with a government that has not been exactly pro-US lately.

But wait. Bolivia doesn’t produce any lithium; the world production leaders are Chile and Australia, each with about a third of the world’s lithium, and China in third place with about 18%. Chile has half the world’s reserves and China has another quarter. Bolivia isn’t even on the list of producers or those with reserves. What’s up?

It’s the difference between resources and reserves. Reserves – what Chile and China have – are known, established deposits that can be mined economically with today’s technologies and at today’s prices. Resources are known, speculative, and possible deposits that might be producible sometime in the future. Huge lithium resources – a third of the world – are what Bolivia has (or may have).

Bolivia also has 6% of the world’s tin, 6% of the silver, 4% of the zinc, 2.5% of the lead, 2% of the antimony, 2% of tungsten, 1.5% of boron. Of all those, zinc is most valuable to Bolivians, contributing around $680 million a year to the national economy, more than silver ($610 million) and tin ($260 million). But Bolivia’s most valuable commodity is natural gas, accounting for most of the $880 million attributable to fuels.

The most important commodity imported by the US from Bolivia is tin. The US imports about 70% of its tin; the rest is not mined but is produced from recycled materials. Of 37,000 tons of tin imported by the US, 16% comes from Bolivia, placing it #2 as an import supplier after Peru, which supplies more than half the tin imported to the US.

Electrical applications use more than a quarter of our tin, well ahead of the #2 use in cans and containers.

Friday, April 1, 2011

Unobtanium comes into its own

Unobtanium, a rare organo-metallic sulfide, now exists in adequate quantities to begin to see common, everyday uses. Its geologic occurrence, near volcanic flows in organic-rich subtropical environments, has limited its use to a few research labs. New devices are beginning to make use of its special properties.

Unobtanium replaces arsenic in integrated circuits, allowing arsenic to be used in more traditional ways. In the near term, this will likely double the cost of cell phones but predictions of increased demand will drive the price down within the next 35 years. Unobtanium goes pretty far: five ounces can make 765,453 cell phones.

Even pots and pans will benefit from unobtanium coatings, because of its remarkable heat transfer properties. In nature, this quality transmits volcanic heat into groundwater, creating hot springs. Processing unobtanium with irradiated fluorspar from China enhances the heat transfer and makes it stronger.

Only a few deposits are known that are rich enough for unobtanium to be mined as a primary product. Not surprisingly, most of these deposits are in China. The Wǒ zhèngzài zuò zhè jiàn shì deposit near the Mongolian border has yielded 67% of unobtanium produced to date. A low-grade deposit on the island of Jensaiqua in French Polynesia is being evaluated for its potential.

Soon most Americans will be importing yet another commodity upon which they will rely without even knowing about it. APRIL FOOL! :)

Wednesday, March 30, 2011


By Richard I. Gibson

Visit this post for a 2013 update on gallium.

Gallium, named for France, comes to the US ironically from Germany, while the biggest proportion of imported germanium comes from Belgium. Both elements are byproducts yielded by refining other metals. Bauxite (aluminum's ore) and zinc processing are the main sources for gallium.

Why care? Most Americans own some gallium. Its biggest use - more than half - is in integrated circuits as gallium arsenide or gallium nitride, and it ends up in cell phones (especially "smartphones"), computers, back-lit flat-panel devices and televisions. Gallium also helps make lasers and solar cells.

The US imports more than 99% of its gallium, from Germany first, followed by Canada, China, and Ukraine. Demand and price are surging because of increasing manufacture of smartphones and flat-panel tech and also because of another important use of gallium: light-emitting diodes, LEDs. High-intensity LEDs are growing in volume, impacting demand for gallium. Its price has gone from $450 per kilogram in 2009 to $670 in 2010, and there's no limitation in sight. 

Gallium finds its way to at least six pages in What Things Are Made Of.

Tuesday, March 22, 2011

State rankings

Based on the search words, a fair number of people want to know what the most valuable mineral commodity is for individual states. The following list gives the top 25 states in terms of their contribution to total US non-fuel mineral production for 2010. The percentage of each state's mineral production of the total is given, followed by the mineral commodity that is most valuable in that state. Thus Nevada is #1 in the US, with 12% of the US total, and gold is the most valuable non-fuel mineral commodity in Nevada. Data from USGS.

1 Nevada (12% of US total) gold
2 Arizona (10%) copper
3 Utah (7%) copper
4 Minnesota (6%) iron ore
5 Alaska (5%) zinc
6 California (4%) sand and gravel
7 Texas (4%) crushed stone
8 Missouri (3%) cement
9 Florida (3%) phosphate rock
10 Michigan (3%) iron ore
11 Colorado (3%) molybdenum
12 Wyoming (3%) soda ash
13 Pennsylvania (2%) crushed stone
14 Georgia (2%) clays
15 New York (2%) salt
16 Idaho (2%) molybdenum
17 Montana (2%) copper
18 Ohio (2%) crushed stone
19 Kansas (2%) helium
20 New Mexico (2%) copper
21 Alabama (2%) crushed stone
22 Virginia (1.5%) crushed stone
23 Illinois (1%) crushed stone
24 North Carolina (1%) crushed stone
25 Indiana (1%) crushed stone

I'll list the second 25 in a future post.

Saturday, March 19, 2011

What Things Are Made Of

312 pages. The print-on-demand version is $17.95 + $3.00 shipping; the initial e-version (PDF) is available for $9.99. Additional e-formats in the works. It will probably be cheaper for you (and faster) for you to order through the publisher's site (link above).

Thanks for your support!

Thursday, March 17, 2011

It's a book!

I received the galley print from the publisher today. It looks like a book, feels like a book, smells like a book. It will probably be a few more days before it is "for sale" but of course I'll make a post about that, with links! viii + 295 pages.

Friday, March 4, 2011

A slight change

Now that the book is about to become available - the publisher uploaded it to the printer today, for a check-print for me before it is actually for sale - I'm going to change my approach to the blog a bit.

I'll try to focus on updates, connections to things in the book that supplement and expand on it, and changes and news related to the topics in the book. It's a certainty that some aspects of the book will be out of date as soon as it is printed, because of the dramatic and speedy changes related to some materials. Rare earths come to mind: the demand, diverse uses, and global distribution of rare earths are in the news weekly if not daily. And there will likely be a bit more about oil and natural gas.

The blog and my web site will also become venues for interesting tables of information that I could not reasonably include in the book. And pictures!

Thanks for your interest. The book ought to be available for purchase by the end of March or possibly sooner. I'll post the link here instantly!

Thursday, February 24, 2011


I was going to take a break from going through the commodities list alphabetically to say something about oil, since the price surge due to worries about Libya and the wider region has tripled the visitor count to my oil pages to more than 1,600 visitors a day (up from a consistent average of about 600), but what I would have said has already been more succinctly written. It boils down to "use less," but the complete, good report can be read here.

Friday, February 18, 2011

What Things book: Another update

The book is done and has been accepted by my print-on-demand publisher of choice. It will end up about 316 pages (6x9 paperback format) and will probably cost $17.95 for the printed version, which should be available in a few weeks. Details on electronic versions to come, but it will definitely be available in the Apple iBookstore.

Thanks to all for your interest and support!

Saturday, February 12, 2011


It’s a metal, not an earth, and more abundant in the earth’s crust than silver, gold, or iodine, but the rare-earth element europium is hard to come by. Like most rare earths, it forms few minerals and usually only occurs as traces within complex rare-earth carbonates and phosphates—minerals that rarely occur in economic concentrations.

Europium, discovered in 1890 and named for Europe, has been used mostly as the red phosphor in television tubes. Appropriately, paper euros include europium-based pigments as an anti-counterfeiting device. US postage stamps have used fluorescent europium as well, and it helps make some lasers and medical screening machines.

Like all the rare earths, europium comes mostly from Bayan Obo, China, the deposit that yields most of the world’s rare earths today. China’s largest rare-earth producer, Baotou Steel Rare-Earth (Group) Hi-tech Co., Ltd., had a 2008 capacity of 250,000 tons of rare earths. Only 120 tons was europium. Its price in 2008 was $1,200 per kilogram ($545 per pound), the third most expensive rare earth after lutetium and thulium.

Monday, February 7, 2011

Diamonds aren’t forever

Wait—maybe they are. Industrial uses rather than gems consume most diamonds, and it’s those industrial applications I’m addressing here. About 55 million carats of natural industrial diamonds were mined in 2010, with Russia in a small lead over Congo (Kinshasa) for production. Together Russia and Congo mined more than half the world’s industrial diamonds.

Diamond in matrix. USGS photo.
In contrast, about 74 million carats of gem diamonds came to light in 2010, with Botswana in the lead and Russia at #2. But wait again—that’s more than the volume of industrial diamonds mentioned in the first paragraph. Right. Those were natural industrial diamonds, which account for only a little more than one percent of all diamonds. Synthetic diamonds dominate the industrial scene, and China produces more than 4 billion carats each year, far and away the world leader.

And guess what? China is the leading supplier of such diamonds to the US, and the US, as expected, is among the world’s greatest consumers of industrial diamonds. The US produces only about 127 million carats of industrial diamond, which sounds like a lot, but not in comparison to that 4-billion-carat gorilla, China. The US imports more than 500 million carats, 63% from China. The few natural industrial diamonds imported come from Africa, largely Botswana, but 93% of US industrial diamonds are synthetic.

Where do they go? Tiny dies for creating thin, light-bulb-filament wires, drill bits that find oil and gas, and computer chips all use industrial diamonds. But the vast majority go to a mundane use: stone and concrete cutting, mostly in the road-building and repair industry.

So as you motor down the highway, think about those Chinese synthetic diamonds. They helped find the oil to make the gasoline in your tank, and they help make the road beds upon which you drive.

Photo: Diamond in matrix. From USGS.

Sunday, January 30, 2011

Cadmium: batteries, TVs, plastics

Greenockite from Tsumeb, Namibia. 
Nobody mines cadmium. It comes from metal refineries, mostly zinc processors, where it is recovered as a trace component. It’s toxic, and not much goes a long way—only about 228 tons in the US in 2009 (down from 700 tons in 2005), with nickel-cadmium batteries (NiCd) leading the way. As lithium ion batteries, with greater energy density, take over in many small devices, NiCd batteries have declined in use, but they may return as storage batteries for on-grid solar energy systems that store electricity during the day and make it available at night.

China produces about a quarter of the world’s cadmium, and while the US is a net exporter, it ranks #9 in world cadmium production with about 4% of the total. A lot of US cadmium is exported to Asia where batteries are made.

Cadmium’s minor uses include photovoltaic devices such as photocopiers, where cadmium sulfide coats drums. Traditional uses include yellow, orange, and red pigments: yellow no-passing stripes on highways once contained cadmium. It also stabilizes plastics, makes lasers, and in phosphors gave the bluish tint to black-and-white TV sets in the 1950s. Cadmium was also once a low-melting component of solder and Wood’s metal—an alloy of bismuth, lead, tin, and cadmium sometimes used in the fusible valves found in automatic sprinkler systems. Wood’s metal melts at 158°F; when fires reach that temperature, the metal melts to open the valve, allowing water to flow.

The only noteworthy cadmium mineral is greenockite, cadmium sulfide, which forms pretty honey-colored crystals shaped like hexagonal barrels.

Photo by Christian Rewitzer, via Wikipedia under creative commons license.

Monday, January 24, 2011

Barite helps find oil

Barite roses from Kansas. R.I. Gibson photo.
Barite is a fairly common mineral, barium sulfate, frequently represented in collections. Its noticeably high specific gravity, 4.5, together with interesting crystals and occasional fluorescence make it popular with mineral collectors. Iron-bearing red sand incorporated into its crystalline aggregates makes barite roses, the state rock of Oklahoma. Gypsum crystals with sand in their matrix make similar “desert roses.”

From 2005 through 2008, the US consumed more than three million tons of barite each year. This volume fell to under two million in 2009 thanks to the recession and its impact on oil and gas consumption because 95% of all the barite used goes into drilling fluids for oil and gas wells. Barite’s density helps control high subsurface pressures.

Barite finds its way into many other uses, volumetrically smaller than oil and gas drilling but more directly pertinent to consumers. It helps protect metal in brake linings and adds gloss to automobile paint. Truck mud flaps, auto tires, home carpet backings, and playing cards include barite for weight, strength, and stiffness.

As a radiation blocker, barite shields x-ray machines and nuclear reactors, and creates the x-ray-opaque contrast medium for intestinal soft-tissue scans. A use that is declining as flat-panel technology expands is in the glass of cathode-ray tubes, where barium carbonate reduces radiation from old-style televisions and computer monitors.

About 80% of US barite is imported, virtually all of it (93%) from China, world leader with more than half the production (India is #2 with about 15%). The 20% of US consumption mined domestically is mostly from Nevada; the US industry employs about 330 workers in a $20 million business, representing about 7% of the world’s barite.

Photo: Barite roses from Kansas. Photo by Richard Gibson. 

Wednesday, January 12, 2011


Orpiment (arsenic sulfide)
Arsenic is Bad Stuff. It may have contributed to Napoleon’s death (accidentally or otherwise) and its presence in water supplies is an ongoing concern. For many years the wood treatment industry in the US consumed most of the arsenic used here, because it is an excellent preservative and insecticide. But toxicity issues led the industry to voluntarily cease using chromated copper arsenate for human-contact lumber like decks and picnic tables in 2003. Total US arsenic consumption has fallen from more than 30,000 metric tons in 1998 to 3,600 tons in 2009.

But arsenic finds its way into a lot of other critical but low-volume uses. It strengthens grids in lead-acid batteries, combines with other metals in some ammunition, and is a vital component of semiconductors in solar cells, circuit boards, and telecommunication electronics. Light-emitting diodes (LEDs) in computers, CD players, and numerous other household electronic devices contain gallium arsenide phosphide in tiny amounts. Two pounds of gallium arsenide can make 500,000 LEDs.

There are some arsenic ore minerals, mostly arsenic sulfides like lemon-yellow orpiment and red-orange realgar, but the primary ore is arsenopyrite, iron arsenic sulfide. It is also common in other minerals mined for elements like copper, and arsenic contributes significantly to environmental problems in copper-mining regions.

All US arsenic is imported. 86% of arsenic metal comes to the United States from China, which produces about half the world’s arsenic.

Orpiment photo from USGS via Wikipedia (public domain).

Friday, January 7, 2011


I recently completed an article on Montana sapphires for Distinctly Montana Magazine, focused on beautiful gems from Yogo Gulch. But sapphires have practical uses too.

Because rubies (red) and sapphires (famously blue, but also pink, yellow, green, purple, and even colorless) are nothing more than corundum, aluminum oxide, with some interesting trace elements (mostly titanium and iron), they are very hard—number nine on the Mohs Hardness Scale, second only to diamond. Consequently they find their way into watch and clock bearings, and those that don’t make the cut as gems are sometimes used as high-quality abrasives.

The first lasers, in 1960, used synthetic rubies to focus light into a coherent beam. Solid-state integrated circuits sometimes use sapphires formed into small thin wafers as their insulating substrate. Larger sheets built from synthetic sapphire sometimes make tough windows in armored vehicles, as well as mundane surfaces such as grocery-store barcode scanners where scratch resistance is valued. High quality watches may have sapphire crystal faces in addition to gem-like bearings inside.

Even though Auguste Verneuil invented a process for making synthetic sapphires in 1902, natural sapphires were used for non-jewel applications for decades after that. Today about 250 tons of synthetic sapphires supply the world annually with watch bearings, abrasives, and specialty uses. The US and Russia manufacture most synthetic stones, while Madagascar is the leading gem sapphire producer.

Watch for the article on Montana’s Yogo sapphires in the Summer issue of Distinctly Montana.

Image: The 182-carat Star of Bombay star sapphire, via Wikipedia.