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| [136] How minerals and gemstones are formed |
Do you know what diamonds, rubies, and emeralds are? "Jewels" is the answer most people offer. It's an accurate answer, but it doesn't tell the fascinating story behind these treasures from nature.... (2001)
 Complete Story |
| Show me more articles from: [Ganoksin]|[Sandra I. Smith] |
| Releated Categories: [Gemology] |
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| [96] Introductory Gemmology - Definitions Concerning Physical Properties of Gemstones |
A perfect crystal is bounded by plane faces which meet at angles specific for each kind of material (angle analysis can identify minerals). A crystal may be cleaved in directions related to the external form or to a possible crystal form for the mineral. Sometimes two distinct minerals can have the same chemical composition with their differing properties being due to their different crystal structure. Crystal structure affects mineral properties.... (1997)
Complete Story |
| Show me more articles from: [Brain Press Publications]|[Charles Lewton-Brain] |
| Releated Categories: [Gemology] |
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| [100] Minerals, Crystals and Their Systems. |
A Mineral may be defined as a homogenous substance produced by the processes of inorganic nature having a chemical composition and physical properties which are constant within narrow limits. Its structure is crystalline. It is composed of the same substance throughout. Except for impurities it has the same chemical formula for all specimens of the mineral. Its atoms usually have a definite and ordered crystal structure. What makes a mineral.... (1994)
Complete Story |
| Show me more articles from: [Brain Press Publications]|[Charles Lewton-Brain] |
| Releated Categories: [Gemology] |
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| [126] Mohs - On A Scale of One to Ten |
Although gemstones are hard substances, they aren't indestructible. Some can be ruined by contact with certain chemicals, while others break easily. Many are susceptible to surface scratching, which can ruin them.... (2001)
Complete Story |
| Show me more articles from: [Ganoksin]|[Sandra I. Smith] |
| Releated Categories: [Gemology] |
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| [102] Notes on Gemstone Fluorescence |
Fluorescence is the emission of visible light from a substance under the stimulation of radiation of a shorter wavelength. It may be stimulated by (visible) light but most useful are blue light, short wave ultra-violet (UV) light, long wave UV and x-rays. Daylight contains some ultraviolet light and some artificial light sources (i.e. photoflood lamps) put out a considerable amount of UV light. An example of the effects of such light is blue fluorescing diamonds. Diamonds which fluoresce blue in UV light may have a yellow tint to them in UV free white light which is cancelled by the blue fluorescence in (daylight) conditions.... (1994)
Complete Story |
| Show me more articles from: [Brain Press Publications]|[Charles Lewton-Brain] |
| Releated Categories: [Gemology] |
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