Column: Emeralds are the rarest of gems

Published 11:51 am Thursday, February 8, 2007

By Staff
Before I get into this week's topic, here's one for you birders. The other day I was out shoveling white rain, which was still coming down in epic proportions, it was minus two degrees and a phoebe was entertaining me with song! He's not even supposed to be here, much less singing cheerily in a below zero blizzard. Optimistic chap.
So, onward. If you caught last week's column on sapphires and rubies you know we're taking a look at some of nature's most spectacular creations, gem stones. There are only four that satisfy the criteria of beauty, durability and rarity to be called precious gems, diamonds, emeralds, sapphires and rubies. All the rest are classed as semi-precious. Actually, it's a bit of a stretch to include emeralds in the big four for they aren't as durable as the other three. Diamonds rank 10 on the hardness scale, the hardest natural substance known to man. Sapphires and rubies are close behind with a rank of 9. Emeralds are only 7.5, though still harder than most other stones. Most detracting, however, is that virtually all emeralds have cracks and fissures in them that affect their toughness. The more inclusions, the weaker the stone.
Despite these shortcomings, high quality emeralds are the most expensive of all gems, commanding higher prices than even diamonds. High quality emeralds of modest size run as much as $10,000 a carat, and anyone that has shopped for a diamond ring can testify a carat ain't all that big. Larger, high quality emeralds weighing several carats can bring as much as $30,000 a carat. This high value is largely due to their rarity.
Emeralds are composed of a mineral called beryl. Pure beryl is colorless but with just the right amount of chromium included the stone is green, an emerald. Oddly, if you'll recall from last week it's also chromium that makes a ruby red. Ruby, red, emerald, green, go figure. Beryl is found in a variety of colors but anything other than the rare green shade is just colored beryl, a semi-precious stone. Emeralds first became prized by man about 4,000 years ago. These came from the India region. Indian emeralds are not of the best quality as they are a rather dull green. Later, Pakistan, Austria and Egypt also became producers. It wasn't until the Spanish Conquest of South America that truly fine, bright, sparkly emeralds emerged. The Spaniards went nuts over them and relieved the Mayans of all they could get their hands on. However, the natives never revealed the location of their emerald mines and to this day those mines remain lost. There's a project for you aspiring Indiana Joneses.
Today, Columbia and Brazil still produce the finest emeralds in all the world. About 50 years ago emeralds were also discovered in parts of Africa, most notably what is now Zimbabwe and Zambia and to a lesser degree, Tanzania. There is some troublesome stuff here for the emerald trade. Zambia does not allow export of its emeralds, which have a unique bluish cast to them. However, these emeralds are magically finding their way into the emerald pipeline. To retain respectability the trade labels them as Zimbabwe emeralds but they're not fooling the experts. At any rate, everyone seems happy with the arrangement. A few emeralds are found elsewhere, such as Russia and even the southeastern U.S. Many of these, though, attain their green color from vanadium rather than chromium and some purists refuse to recognize them as emeralds.
Centuries ago it was discovered soaking emeralds in oil made the inevitable fissures less visible and the color brighter. This is still commonly done today and is acceptable as long as the oil isn't tinted green to falsely enhance the color. Of course, the oil eventually dries out, which calls for an occasional re-oiling. Epoxy is now replacing oil, which is a more permanent fix.
If you find an emerald with a price too good to be true it probably is. Like rubies and sapphires, man made emeralds are common. These you can usually tell because they are a more sparkly, lighter green. Verify that it's the real deal before laying down big bucks. Carpe diem.