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Pure Yellow and Modified Yellow
The most desirable color for a yellow diamond is pure yellow. However, most yellow diamonds have at least traces of a secondary color. Greenish yellow and orangy yellow are common modifications of yellow color in diamonds. Although pure yellow is the favorite, many people enjoy the modified colors and are happy to get them at…
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Isn’t Yellow Color a Bad Thing?
Nearly all gem-quality diamonds are graded on a color scale that most highly values the absence of color. The most widely used color scale for grading diamonds is the D-to-Z color-grading scale developed by the Gemological Institute of America (GIA). On the GIA scale, a grade of “D” or “colorless” is the highest grade. Traces…
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What Are Yellow Diamonds?
Yellow diamonds are diamonds that have an obvious yellow bodycolor when viewed in the “face-up” position. The yellow color is usually caused by small amounts of nitrogen contained within the diamond’s crystal structure. Yellow diamonds with a rich, pure yellow color are the world’s most valuable yellow gemstone. Many people consider them to be the most beautiful yellow…
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Use of Jet and Jet Substitutes Today
As a fashionable item, jet declined quickly during the Great Depression when the demand for manufactured goods of all kinds collapsed. It never regained its Victorian popularity and is used infrequently today. Jet is one gem material that has been heavily replaced by look-alikes and imitations. When jet was popular, materials such as black glass and gutta-percha…
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History of Human Use
The most important source of jet has always been the eastern coast of England and Scotland, centered near what is now the community of Whitby. In this area people found small, black, rounded, light-weight stones along the shoreline. They discovered that these stones could easily be fashioned into beads and other objects and could be polished…
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Physical Properties of Jet
Jet has a few properties that make it useful and desirable. These have dictated its use across the centuries. The first of these properties is its ability to be easily carved or cut into shapes. Jet is soft and has a uniform texture, which allows it to be carved with precision. Jet can be rubbed…
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“Hard” and “Soft” Jet
Craftsmen who work with jet recognize that material from some areas is much harder than that from others. The “hard jet” tends to be associated with bituminous shales that were deposited in salt water, while the “soft jet” tends to be associated with bituminous shales that were deposited in freshwater environments. Jet found in the…
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How Does Jet Form?
The material known as “jet” is very similar to coal, but the way that it forms is different. Most coal seams form when a swamp containing abundant woody material is buried; that woody material is then compacted, undergoes organic degradation, and is heated. The result is a coal seam. Jet does not form in a…
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What is Jet?
Jet is a black organic rock that forms when pieces of woody material are buried in sediment and are coalified. Though very similar to coal, it is less friable. Jet can be cut, carved, and polished to a bright luster. People have used jet for thousands of years to produce gemstones, beads, and many other objects. Jet is one…
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Appropriate Names for Diamonds
A wide variety of names have been used for diamonds that have been made by people. In the early days, the names “synthetic diamonds” and “man-made diamonds” were most often used. Synthetic diamonds was the more scientific name and the name used among technical people. Man-made diamonds was a name used by much of the…