Mineralogy

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The Ochtinská Aragonite Cave in southern Slovakia is one of only a handful of caves in the entire world where aragonite crystals are found. Argentina, Brazil, Mexico, and the United States each have one as well. 

The cave was discovered accidentally when miners digging for iron accidentally breached the walls of the cave system in 1954. Since then, over 30,000 visitors have traveled there to witness its natural beauty. 

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TOP TEN RAREST GEMSTONES

Note: This list is in reverse order, unlike most of my top ten lists.

1. Tanzanite - Found only in the foothills of Mount Kilimanjaro, it is expected than tanzanite will be mined out within the next twenty to thirty years. Market value: $600-$1000 per karat.

2. Taaffeite - Pronounced ‘tar-fite’ and found in colors ranging from nearly colorless to lavender, mauve and violet, only a handful of these gems have ever been found, mostly in Sri Lanka and Tanzania. Market value: $1500-$2500 per karat.

3. Black opal - Almost all black opal comes from a single mine in New South Wales, Australia. Market value: $2355 per karat.

4. Benitoite - Benitoite is the official state gem of California due to the fact that it is found almost exclusively near the San Benito River, which flows through California. A few specimens have been found in Arkansas and Japan, but its only commercial mine is located in California. It also glows when placed under UV light (picture). Market value: $3000-$4000 per karat.

5. Red beryl - Also known as ‘bixbite’ or ‘Scarlet emerald’, red beryl is found exclusively in the American states of Utah and New Mexico. Market value: $10,000 per karat.

6. Alexandrite - Named for Tsar Alexander II of Russia, Alexandrite has color-changing properties which makes it both unique and rare among gemstones. When exposed to incandescent light (such as candlelight), it appears to have a pink hue; but when exposed to daylight, its color changes from pink to green. You can watch a video of it changing color here (video). Market value: $12,000 per karat.

7. Jadeite - Although its name resembles the semi-precious gemstone jade, jadeite is actually many times more valuable than its less common counterpart. Jadeite is found only in limited quantities in Myanmar. Market value: $20,000 per karat.

8. Musgravite - A precious gem in the same family as taaffeite, this mineral’s color ranges from purple to a brilliant greenish grey. Although very small quantities have recently been found in Greenland, Antarctica, Sri Lanka, Tanzania, and Madagascar, for several decades there were only eight known specimens of this rare gem. Market value: $35,000 per karat.

9. Painite - Only a handful of these reddish-brown crystals have ever been discovered, and only in Myanmar. Up until a few years ago, only two specimens had ever been found. Market value: $50,000-$60,000 per karat.

10. Pink Star diamond - The Pink Star diamond is a “fancy vivid pink” diamond that was mined in South Africa in 1999. Weighing in at 59.6 karats, it was sold by Sotheby’s for a record $83 million - more than any other gem ever sold. That’s about $1,395,761 per karat.

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Liz Butler Draws The ROM: Earth’s Treasures

Hi ROMKids!

This week I was out in the Teck Suite of Galleries: Earth’s Treasures, looking at rocks and minerals. I have to admit, I was pretty nervous to sketch in these galleries, because the displays are so beautiful all on their own!

While I was in the galleries, I drew images of quartz (shown here in purple, which does not show the actual colour of the specimen) and calcite (in red and green - also not the true colours of these crystals). While it may be obvious when you look at them that rocks and minerals have long been valued for their lovely appearance, you may be surprised to learn that these materials also play an important role in technology!

Quartz crystals of a high quality have historically been used in mechanical devices because they can convert electrical energy to mechanical energy (movement), or the reverse (piezoelectricity). This amazing property means that many common items around your home contain quartz crystals.

Calcite, meanwhile, has a very unique ability to affect light. In fact, calcite has been in the news recently because some engineers have been able to make small ‘invisibility cloaks’ using the special light-refracting properties of calcite! The cloaks do not resemble the more famous robes from Harry Potter, but the small crystal structures have been used to hide objects that are otherwise visible to the human eye.

Interested in the outstanding properties of rocks and minerals?
Do some research about devices found around your home. You might be surprised to find that there are precious materials like diamond and gold hidden in your living room, or that the rocks and minerals around your home have been mined from distant countries around the globe!

More info:

  • Liz Butler is an artist and teacher who loves natural history and museums. She loves drawing, painting, and making crafts of all kinds. She is happiest when she can find ways to combine art projects with science content.
  • Liz’s WebsiteLiz Butler Draws, Liz’s BlogSaw Whet Studio
  • Find EVERY post of Liz Butler Draws The ROM HERE!
  • Do you like to sketch? Love museums? Are you a full time student in Canada? The ROM is yours to explore, FREE, every Tuesday! MORE!

Guest Post By Liz Butler. Last Updated: August 14th, 2015.