Treasures from the Earth
"No thief, however skillful, can rob one of knowledge, and that is why knowledge is the best and safest treasure to acquire"― L. Frank Baum,
Gemstones are timeless treasures of the earth that not only represent objects of beauty & intrigue, but also represent some of the more valuable commodities on earth.
The extraordinary & satiated colors of many gems enhance their aesthetic beauty, while others produce extraordinary fire, birefringence or other attractive light interference. When mankind first picked a stone from the ground for its innate beauty rather than as a tool or weapon, this symbolized an important event in evolution. When this stone was given to another as a gesture of friendship or love: an unique quality of the human soul was manifested in sharing.
This evolution led to the search for similar rocks & minerals. The recognition of certain characteristics in a particular stone and its association with nearby specific rock types such as agate or jasper in grey to white rock (limestone) or other varieties of quartz in vugs of milky white and pink rocks (pegmatites), greatly enhanced the ability of the first prospectors to find additional stones of similar quality. Recognition of such mineral & rock associations signaled the start of the science of prospecting. As time passed, these primitive prospectors exchanged ideas & concepts that ultimately led to the science of economic geology.
Recognizing rock and mineral associations & understanding regional geology is important in a search for new gemstone deposits. In this search, the successful prospector must not only focus on regional geology, but also on surrounding host rocks, mineral & rock associations & geological environments. Like any other mineral, gemstones grow under specific physical & chemical parameters. Some have innate characteristics that allow survival during weathering, erosion, stream-transportation & placer concentration. Gems may be found in igneous, metamorphic, and/or sedimentary environments & typically are associated with specific rock types & mineral suites. Unlocking these characteristics & clues can lead geologists to the discovery of additional deposits.
Gemstones are sought for personal adornment & have become prized possessions of men, women, kings & queens. Some of the more exotic minerals & gems represent the most valuable commodities on earth based on size. Few things on earth can compare to a fabulous gemstone. The rare pink Padparadscha sapphires from Sri Lanka bring high prices. But it is the blue sapphires that usually bring the highest price for sapphire. One 62-carat royal blue rectangular cut sapphire was valued at $2.8 million. In 2007, another blue Kashmir sapphire of 22.66 carats sold for US$3,064,000, or $135,216/carat! All for a polished crystal!
In general, rubies are more valuable. In 1998, a Burmese ruby of 15.97 carats sold at a Sotheby's auction for US$3.63 million. In 2005, Christie's of New York sold a near perfect, 8.01-carat Burmese ruby for US$2.2 million. In 2011, Elizabeth Taylor's jewelry was auctioned by Christie's: one notable 8.24 carat ruby sold for $4.2 million. In 2012, the Etcetera Burmese ruby sold at a Christie's auction for US$3.3 million, an astounding $551,000/carat.
Some rough jade of unimaginable value include a 1.4-inch long jadeite cabochon that sold for US$1.74 million. In 1999, a jadeite bangle only 2 inches in length & 0.3 inch wide sold at a Christie's auction in Hong Kong for US$2,576,600. Even more incredible was a 27-bead emerald-green jadeite necklace, known as the Doubly Fortunate that sold for US$9.3 million in 1997. Periodically, enormous jade boulders and cobbles are found.
Some of the more valuable diamonds are red & pink. A small 0.95-carat purplish-red diamond (the Hancock Red) sold for nearly US$1 million. To put this in perspective, one carat weighs only 0.2 gram (0.007 ounce). At 2009 gold prices, this diamond was valued at >200,000 times an equivalent weight in gold - a common value for flawless pink diamonds. Another pink diamond of only 24.78 carats (large for a pink) sold for the highest price ever at a Sotheby's auction in 2010. The winning price - $46 million ($1.86 million/carat). This beat the earlier 2008 record price for the Wittelsbach-Graff blue diamond of 35.56 carats. Still, the most notable of all diamonds was the Cullinun rough, the largest ever found at a whopping 3,106 carats. The diamond was priceless and the finished gems embed the crown of England.
Gemstones have intrinsic properties that make them attractive: others stimulate our imaginations with unique qualities. The value of some gems has reached extraordinary heights due to ingenious marketing ploys such as a group of former industrial diamonds that are now coveted by the wealthy. These include brown diamonds, once considered to be almost worthless, but today are marketed as rare cognac & champagne diamonds. Yellow diamonds, also considered low-value stones in the past, are now marketed as Canaries. And we are now seeing chocolate diamonds - diamonds that would have brought a bitter taste to any gemologist a few decades ago. But people stand in line to purchase these once, worthless, diamonds. There is little question that some fancy diamonds top all other gems, in value.
Other gems, such as green and blue zoisite, were brilliantly marketed as Tanzanite. For the economic geologist, it is important to note how valuable gems are in comparison to other commodities. Few geologists understand the value or characteristics of gems - a direct result of geology faculty in our universities lacking understanding of gemstones, until they head to a jewelry store to buy a diamond for Christmas.
Tapping into geological knowledge allows geologists & prospectors to predict where gemstones will be found and in what types of rocks will be their host. Such information can lead to significant discoveries, such as the diamond deposits of the Canadian Shield in the 1990s, the poly-gemstone deposits (iolite-ruby-sapphire-kyanite) in Wyoming, discovery of many incredible opal deposits in Australia, and one of the largest gold deposits on earth.
This educational site is for you, the layman, prospector, treasure hunter, rock hound, dentist, mechanic, doctor, housewife, geoscientist, etc. It contains information & methods used to find diamonds, colored gemstones & gold. Over 3 to 4 decades, I found several hundred precious metal & gem deposits including a few that are world class. Some sat right under the noses of people for decades simply because they didn't look. Diamond deposits were found adjacent to Interstates & US Highways in Colorado & Wyoming. World-class colored gem deposits with stones as large as Smart cars were found between 1995 & 2005 in Wyoming, and peridot gems were found at sites examined and described by many geologists.
The largest colored gemstone deposit in the world may also have been found in 2005: estimated to have >2 trillion carats of gems! A large opal-agate deposit was found adjacent to a US Highway within an petroleum field used by many people weekly - some opals >70,000 carats were identified in roads, in this field. More than a dozen ruby deposits were discovered including some of the larger rubies in the world simply by looking for rocks known as vermiculite schist, serpentinite and glimmerite. There are more deposits you will read about on this website & how using common sense, geology & geochemistry, led to their discoveries. Start looking at Google Earth and at geology publication archies - and with a little knowledge, you might find and King's ransom in gemstones.