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Introduction:
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Diamond is the hardest mineral known to man. It is remarkably 140 times harder than ruby and sapphire, which are the next hardest gemstones. Most widely known in its colorless form, diamond also occurs in other "fancy" colors including deep yellow, brown, pink, blue, and green. These fancy colors are sometimes drawn out of light yellow stones by using irradiation. Eighty percent of the diamond market is managed by a conglomorate of companies known, in short, as "De Beers." Sorted and valued diamonds go from mines to the CSO in London where they are sold, in the rough, to a select few accredited cutters and traders. The lots are resold and enter the retail market by way of diamond exchanges and the purchases made there by direct buyers. Some of these exchanges are located in Antwerp, Amsterdam, New York, Israel, and Johannesburg. |
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History
of...
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Prior to 1871, diamonds were mined from secondary deposits only. This means diamond from deep within the earth was transported by magma and water to locations closer to the surface where it could be discovered. When primary "pipes" of diamond-bearing rock were discovered in South Africa, diamond mining began. Originally the diamonds were mined in an open pit, but shaft mines are used today. The Kimberly mine is the first open pit diamond mine. It was mined froom 1871-1908. 14.5 million carats were recovered from the Kimberly mine. Today the mine, which was once the largest man-made hole on the planet, is half-filled with water.
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Technical
Specifications:
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| DESCRIPTION |
| Diamond is a mineral species. |
| Chemical
Composition: |
C |
| Appearance: |
•Transparent to opaque
• Diamond is widely known in its colorless form, but it is commonly found in a range of colors from very light yellow to brown to gray. More rarely, fancy-colored diamonds occur in a spectrum of colors including darker yellows and browns, very light to dark blues, greens, orange, pink, red, and purple. Black stones are occasionally cut as gems. |
| Misnomers: |
None known |
| Typical
Sizes: |
Melee sizes to about 5 carats; Cut stones of several hundred carats exist |
| Cut Styles: |
Faceted |
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| IDENTIFICATION |
| Optic
Character: |
SR |
| Refractive
Index: |
2.417 |
| Birefingence: |
None |
| Dispersion: |
.044 |
| Pleochroism: |
None |
| Ultraviolet
Fluorescence: |
Colorless to yellowish stones--inert to strong, usually blue (LW), weaker (SW) |
| Absorption
Spectra: |
•415.5 nm line in cape series
•When cooled to low temperatures, irradiated and annealed stones often show a thin line around 594 nm |
| Cause
of Color: |
?Yellow, Orange: Nitrogen & related color centers
?Blue: Boron
?Green: Color center due to irradiation (natural or artificial)
?Red, Pink, Brown: Unknown, possibly structural anomalies |
| Specific
Gravity: |
3.52 (+/-.01) |
| Polish
Luster: |
Adamantine |
| Fracture: |
Step-like |
| Luster: |
Adamantine |
| Cleavage: |
Perfect in four directions |
| Indentifying
Characteristics: |
Naturals, waxy to granular girdle surface, bearding, sharp facet junctions, angular inclusions, no see-through effect, thermal inertia higher than simulants, adamantine luster |
| Known
Enhancements: |
• Fancy colors can be drawn out of light yellow, brown and possibly gray diamonds by irradiation followed by controlled heating. This practice is common and stable.
• Coating is occasionally used to mask unattractive color. The coating can scratch and coated stones should not be repolished.
• Cracked stones are sometimes enhanced by filling in the cracks. One should avoid heat and solvents when working with cracked stones. |
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| DURABILITY RATINGS |
| Hardness: |
10 |
| Toughness: |
Good in cleavage directions; Exceptional in other directions |
| Diamond is sometimes mistaken for: In legitimate jewelry trade, diamond is not likely to be confused with other stones. However, colorless diamond looks similar to rock crystal, precious beryl, cerussite, sapphire, scheelite, spahlerite, topaz, and zircon. Various synthetics are fabulite, YAG, galliant, djevalite, linobate, and cubic zirconia. |
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Care
Tips:
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| Cleaning Methods |
| •Ultrasonic: |
Usually safe on stones without feathers |
| •Steamer: |
Usually safe on stones without feathers |
| •Warm
soapy water: |
Safe |
| Stability of Stone |
| •Heat
tolerance: |
Begins to vaporize in an oxygen-rich atmosphere at 690° C to 875° C |
| •Light
tolerance: |
Stable |
| •Chemical tolerance: |
No known reactions to chemicals |
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Recommended
Uses:
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Rings
- Diamond rings are obviously the most popular form of diamond use. The durability of diamonds is unmatched by any other substance and is therefore best used in a ring setting. Earrings
- The only reason not to use diamonds in earrings is that they may be misplaced or lost. Diamonds are quite expensive and would be costly to replace. As far as beauty, durability and flexibility, diamonds are a perfect choice for earrings.
Pendants - Once again a great choice for popularity and durability.
Bracelet - Depending on the size of stones needed for the bracelet, diamonds are a great choice for a bracelet. This could be a costly piece of jewelry but well worth the investment.
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Source
Map:
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| All technical specifications and care
tips on this page was referrenced from the "Gem
Reference Guide" published by the Gemological Institute
of America |
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