Each month this section will feature either a topic of interest to gem lovers or one special gemstone with background on the material and its value.

Go to: Homepage -- what's new at ACS -- monthly specials and discounts -- "buried treasures" -- BWS/FS jewelry designs -- gem topic of the month -- gem topic archive -- birthstones -- ask Barbara -- key to all the codes used on the ACS site -- definitions of terms used on the ACS site -- how to order -- about ACS -- setting these gems -- free gemology course

-- Mail to barry@acstones.com

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APATITE

Apatite, a stone seldom found in jewelry stores and only recently known to the general public, is beloved by collectors for its many different colors and forms. Only with the recent availability of the neon blue-green variety from Madagascar has its jewelry use increased. The color of the best specimens of this type rivals the famed Paraiba tourmalines, but alas, this gem lacks their toughness and hardness. At 5 on the Mohs scale, and a tendency to cleave, apatite must be cut, set, and worn gently. Earrings, pendants, pins and tie tacks are probably safe, but ring and bracelet use should be limited to occasional wear pieces with protective settings.

 

[Green apatite rough, showing some cleavage surfaces]

Care for this stone is similar to that given opals, it is heat and shock sensitive, so steamers and ultrasonics must be avoided. Only occasionally cut as cabochons and beads, the greatest use is in faceted stones.

[Dark blue apatite protectively set in earrings, a set of apatite cabochons]

 

Gems are available in yellows and various shades of blues and greens, some of the blues and yellows show chatoyancy and can be cut as cat's eyes. Main sources are Brazil, Canada, India, Mozambique and Madagascar.

[Yellow, medium blue and dark blue apatite gems]


Value

In today's market, the neon blue green stones are valued much more highly than green or yellow stones. The rarest of all varieties, a rich purple from Maine, tops the list. Degree of polish can vary on this soft stone due to skill levels of individual cutters, giving well polished stones premium value. As with most gems, saturation of color, size and clarity are the major determiners of value. Cat'seyes also fetch good prices.

[Fine quality blue and yellow apatite cat'seye gems]


Gemological Data:

Makeup: Calcium Phosphate

Luster: Vitreous

Hardness: 5

Crystal structure: Hexagonal

Fracture: vitreous to uneven

Cleavage: imperfect, two directions

Density: 3.20

RI: 1.63 - 1.64

Birefringence: .003

Pleiochroism: depends on color, may be strong to weak

Dispersion: .013


Stones Currently Available:

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Go to: Homepage -- what's new at ACS -- monthly specials and discounts -- "buried treasures" -- BWS/FS jewelry designs -- gem topic of the month -- gem topic archive -- birthstones -- ask Barbara -- key to all the codes used on the ACS site -- definitions of terms used on the ACS site -- how to order -- about ACS -- setting these gems -- free gemology course

-- Mail to barry@acstones.com