Gemstones More Valuable Than Diamonds

Rare Properties That Make Some Natural Gems Highly Prized

Jun 18, 2009

While many people think diamonds are the most precious gems on Earth, some gemstones have unique characteristics that make them much more valuable overall.

Some natural gemstones of good quality are found in colors and sizes so rare they are eagerly sought-after by jewelers and collectors. Some of these precious stones have unusual properties that add to their value, such as the way they capture and reflect light, change color in certain light, or have unique crystal formations within their structure.

Here are four examples of gemstones that have rare and unusual characteristics that often make them more valuable than diamonds.

Alexandrite

A gemstone named after Russian tsar Alexander II when it was discovered in 1834, Alexandrite is a unique crystal that changes color in different light. It is also very scarce, because Alexandrite was formed under extraordinarily rare geologic conditions, where different types of rocks that normally do not coexist were brought into contact with each other, allowing the crystals to grow. Alexandrite is a chrysoberyl containing titanium and iron, but impurities of chromium give it the distinct feature of changing from a bluish-green in daylight to a reddish purple under incandescent lighting.

The original deposits of this gemstone were pretty much depleted from the mines in the Ural Mountains of Russia, until deposits were found in Brazil in 1987. While there are slight differences between the Brazilian and Russian types, any finely faceted specimen over a carat is rare and expensive—especially if it is from a Russian source—and its color change should be dramatic, with no hints of brown or grey coloring.

Demantoid Garnet

While there are many kinds of garnets in the world, some are highly prized for special features. The green colored garnet called “demantoid,” from the Ural Mountains of Russia and mines of Namibia, is more refractive than a diamond when faceted. The high refractive index of garnets in general sets them apart from other gemstones, but the demantoid is especially brilliant. Its green color can vary from yellowish- to bluish-green, with deep green being extremely rare, and while most demantoids after cutting are less than a carat, and rarely larger than two carats, this stone’s brilliance and fire is unmatched, regardless of the shade of green.

The demantoids from the Urals, first discovered in 1868, have a rare feature not found in African demantoids—fine, wispy crystal deposits of chrysotile, called “horsetail inclusions.” Not only will well-formed horsetail inclusions increase the value of this super-brilliant stone, but their presence is an indisputable marker of the stone’s origin.

Ruby

Chromium in the crystal corundum forms the red colored version of the aluminum oxide mineral called ruby. It is very rare to find large pieces of raw, uncut ruby that have no fissures or cracks. Therefore, any piece over 3 carats is highly prized and could bring more at auction than a diamond of similar weight.

The main indicator of value with rubies is the color, which can range from the top-quality “Burmese color” red, which has a bluish tinge, to the deep red “Siamese color” or the light red Ceylon ruby color. The most prized of all, though, would be a rare star ruby. In this stone, the mineral rutile forms the star-shaped deposit in the stone, and when expertly cut, is very valuable.

Blue Sapphire

Sapphires (corundum) are found in a variety of colors, and in fact the red variety of this aluminum oxide mineral is what we call ruby, as explained before. But it is the deep blue, fancy cut sapphires that command a premium in the sapphire trade. While blue sapphires are mined in eastern Australia, Thailand, Colombia, Africa and places in the U.S., such as Montana, Ceylon sapphires (from Sri Lanka) are most respected and prized, and compared to Earth’s diamond deposits, sapphires are much more scarce.

Kashmir color sapphires, a rare blue color akin to those found in the original Kashmir mine of India where these gems were first discovered, are bought and sold today in Sri Lanka. Remarkable specimens of untreated blue or Kashmir color sapphires over 4 carats are investment grade and are most likely obtained through special dealers or at auction.

Buyers who are interested in investing in truly rare gemstones, unlike diamonds which exist in abundance but whose quantities are controlled by suppliers, can learn more about the gems mentioned in this article, and more, by browsing the Mineral and Gemstone Kingdom, or Gem by Gem, the web site of the International Colored Gemstone Association.

The copyright of the article Gemstones More Valuable Than Diamonds in Gemstones is owned by Cheryl Kraynak. Permission to republish Gemstones More Valuable Than Diamonds in print or online must be granted by the author in writing.