|
|
| |
| |
| [547] The Formation of Gem Materials |
The most valuable gems come from crystallized minerals that have formed under heat and pressure deep inside the earth. The perfect order of the crystal structure is what makes gemstones transparent yet durable. Crystallization of minerals is a fairly slow process, to enable it to occur, specific geologic and chemical conditions must be met. Depending on the conditions, the same chemical recipe will crystallize in different crystal structures....
(1999)
 Complete Story |
| Show me more articles from: [Handbook for the Gem Buyer]|[Sondra Francis] |
| Releated Categories: [Gemology]|[Handbook for the Gem Buyer] |
|
| [306] The Origin Blues - Figuring out where a sapphire came from is no easy task |
If each sapphire deposit has its own unique chemical mix, in theory it should only be a matter of careful analysis to figure out where a stone came from. But there remains an element of art to determining country of origin, partially because of the limitations of the science itself, and partially because no one has yet compiled complete data on each gem locality..... (2002)
Complete Story |
| Show me more articles from: [Colored Stone]|[Suzanne Wade] |
| Releated Categories: [Gemology] |
| ISBN: B000060MIL |
| [303] The Secret Life of Rocks |
Think they just lie around? Oh, no! Rocks are constantly meeting, mingling, and occasionally making gemstones....
Every so often you hear about a miner who literally trips over a rock, or takes a good. hard look at the ground in just the right place, and suddenly discovers a gemstone deposit. For the serious prospector, though, finding a deposit requires a good grounding in how the Earth is put together - the different types of rock you encounter and the conditions under which they formed. all of which determine whether or not gems could have grown there.... (3)
Complete Story |
| Show me more articles from: [Colored Stone]|[Martin Stone] |
| Releated Categories: [Gemology] |
| ISBN: B000060MIL |
| [549] The Treatment of Gemstones |
The treatment and enhancement of gemstones has existed for centuries. Some enhancements improve on nature slightly, are undetectable, and they are permanent; this provides the gem market with a larger supply of beautiful gemstones. Other treatments produce dramatic changes in the gemstone; the irradiation and heating of colorless topaz that permanently transforms it into blue topaz is an excellent example. A few treatments are less stable and should be avoided by the knowledgeable buyer..... (1999)
Complete Story |
| Show me more articles from: [Handbook for the Gem Buyer]|[Sondra Francis] |
| Releated Categories: [Gemology]|[Gemstone Treatments]|[Handbook for the Gem Buyer] |
|
| [953] The trouble with Pyrite |
The first reference that I have that links copperas with the collection of fossils is found in the ´Life and letters of Edward Lhwyd (second Keeper of the MUSEUM ASHMOLEANUM) Oxford March 28th. 1695´. Below is an excerpt from ´A Museum of the Early seventeenth Century´ By Cyril Edward Nowill Bromhead, BA, FGS, FRGS. (Read 18Th. June, 1947) referring to the Lhwyd letter....
(2011)
Complete Story |
| Show me more articles from: [Ganoksin]|[Fred Clouter] |
| Releated Categories: [Gemology] |
|
|
|
|
|
| |
