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Introduction:
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The most valuable member of the quartz group is Amethyst, designated for the first wedding anniversary and February birthstone. Amethyst is found in alluvial deposits and geodes in many locations throughout the world. Primary sources for the stone are Brazil, Madagascar, Zambia, Uruguay, India, Sri Lanka, Namibia and Russia. Significant attention and top value goes to African amethyst because stones from that continent possess deep, rich color that is unusual for small stones from other sources. Unfortunately, the African market makes the stones difficult and slow to come by. Many jewelers use South American stones to avoid long waits and pressure to buy in huge bulk. The rich, purple color of amethyst makes the stone very popular in fashionable jewelry. It is often cut into faceted stones, cabochons, beads, or carvings and may range in size from one to twenty carats. Heat treatment is occasionally used to lighten very dark amethyst or remove smoky components in the color. Inform customers that high temperatures may turn amethyst colorless or into citrine. Abrupt temperature changes can lead to fractures. |
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History
of...
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The Greek word amethyst means "not drunken," and Greek mythology provides an interesting story of amethyst's origin. According to legend, Diana turned a beautiful maiden, Amethyst, into a pillar of quartz to protect her from the wrath of Bacchus, who had grown angry with mortals. When Bacchus repented of his anger, he poured libations of wine over the pillar of quartz, staining it purple. Thus, the Greeks believed drinking wine from an amethyst cup or wearing an amethyst amulet would prevent drunkenness. Other associations with amethyst include its power to protect soldiers in battle, control evil thoughts, and make its owner shrewd in business matters.
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Technical
Specifications:
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| DESCRIPTION |
| Amethyst is a variety of the mineral quartz. |
| Chemical
Composition: |
SiO2 |
| Appearance: |
•Transparent material is used for faceted and cabachon pieces while beads and carvings are often time translucent.
•Coloring is bluish purple to purple to reddish purple and may show a minor shift in color in different lighting. |
| Misnomers: |
None known |
| Typical
Sizes: |
1 to 20 carats |
| Cut Styles: |
Faceted, cabachon, beads and carvings |
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| IDENTIFICATION |
| Optic
Character: |
DR, uniaxial positive |
| Refractive
Index: |
1.544-1.553 (very constant) |
| Birefingence: |
.009 |
| Dispersion: |
.013 |
| Pleochroism: |
Weak to moderate purple and reddish purple |
| Ultraviolet
Fluorescence: |
Usually inert and may show weak blue (SW) |
| Absorption
Spectra: |
Not diagnostic |
| Cause
of Color: |
Iron impurities and irradiation |
| Specific
Gravity: |
2.66 (+.03, -.02) |
| Polish
Luster: |
Vitreous |
| Fracture: |
Conchoidal |
| Luster: |
Vitreous |
| Cleavage: |
None |
| Indentifying
Characteristics: |
Color zoning, twinning, liquid, 2-phase and 3 phase inclusions, negative crystals |
| Known
Enhancements: |
Some very dark amethysts are heat treated to lighten the color. Heat is also used to remove smoky components of color. The treatment is undetectable and very stable. |
| DURABILITY RATINGS |
| Hardness: |
7 |
| Toughness: |
Good |
| Amethyst is sometimes mistaken for iolite, scapolite, and synthetic amethyst. |
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Care
Tips:
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| Cleaning Methods |
| •Ultrasonic: |
Usually safe |
| •Steamer: |
Risky |
| •Warm
soapy water: |
Safe |
| Stability of Stone |
| •Heat
tolerance: |
Strong heat turns amethyst colorless or may produce citrine. Sometimes heat produces a green color; however, gentle heating is sometimes used to lighten dark amethyst and remove smoky tones in its color. Abrupt temperature changes may cause amethyst to fracture. |
| •Light
tolerance: |
Some stones may fade |
| •Chemical tolerance: |
Soluble in hydrofluoric acid and ammonium fluoride; very slightly soluble in alkalies |
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Recommended
Uses:
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Rings
- Although quite suitable for a ring, amethyst's low tolerance to heat may be something to consider when mounting in a ring. Frequent exposure to light may also fade the color of an amethyst and if the ring is to be worn often this should be taken in to account. In general amethyst will work well in a ring and will bring many years of enjoyment to it's wearer. Earrings
- Amethysts make for a great pair of earrings. Not only are they affordable but are easily replaced if one is lost as often happens with earrings. Very nice amthysts can be purchased for a reasonable price and will show well in an earring mounting. The ideal size, depending on a customers preference, would be 5m to 6mm. This will offer a good sized stone at a good price and will be noticed by admirers. Ask about checkerboard cuts when inquiring about amethysts. They are great in bezel sets.
Pendants - Because amethyst is available in large sizes and is relatively inexpensive, a pendant is the best use of the stone. Amthysts are quite durable specimens which lends itself to a pendants natural abuse. Not only will an amethyst pendant withstand the occassional banging it will also attract the attention of others. Larger sizes with very deep coloring are obviously going to generate many compliments and are quite likely to spark interest from most anyone they come in contact with.
Bracelet - It is often difficult to find stones to go in a bracelet application. Usually because it requires multiple stones that match in color, size and cut. Amethyst is one of those stones that should be considered for a bracelet application. Not only are they readily available and durable but they are beatiful when matched side by side. Bracelets are not often worn as frequently as rings and will last many years with the infrequent exposure to light.
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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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