Apatite | Gemopedia

Apatite is the name for a mineral group as well as the generic term for many phosphates, but gem-quality apatite is a special gemstone found in a beautiful variety of colors. Apatite's various colors are often due to the presence of rare earth elements or natural irradiation. Because of its wide color range, apatite has often been mistaken for many other gemstones, including topaz, tourmaline, and various beryl varieties. Particularly rare in sizes over one carat, apatite is a relatively soft gem and when used in jewelry manufacture, is often set into more protective mountings that capture light yet safely display its beauty. The long-established sources for gem-quality apatite are Brazil and Mexico, but more recent African discoveries have thrust it into the spotlight once again.
Alternate Names
Fluorapatite, Asparagus Stone, Moroxite
Colors
Yellowish Green, Brownish Green, Green, Violet, Pale Light Blue, Violet-Blue, Blue, Pink, Purple, Yellow, Orange, Brown, Colorless

Apatite Classification

Common Name

Apatite

Species

Apatite

Variety

Colors

Yellowish Green, Brownish Green, Green, Violet, Pale Light Blue, Violet-Blue, Blue, Pink, Purple, Yellow, Orange, Brown, Colorless

Alternate Names

Fluorapatite, Asparagus Stone, Moroxite

Gemstone Groups

Key Separations

refractive index, birefringence, optic character, pleochroism and possibly spectrum

Comments

May show pseudo-biaxial optic figure. Avoid heat and ultrasonic cleaners, and chemicals. Might show abrasions due to low moh's hardness. The name can be translated from Greek as "I am misleading". Most gemstones are Ca5(PO4)3F Calcium Fluroro Phosphate. The light green variety sometimes called asparagus stone. Moroxite is the blue-green variety.

Apatite Optical Properties

Transparency

Transparent - Translucent

Refractive Index

1.634-1.638
Tolerance:(+0.012/-0.006)

Birefringence

0.002-0.008

Optic Character

Uniaxial

Optic Sign

Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: Variable
LWUV: Variable

CCF Reaction

Pleochroism

Dichroic, strong blue and yellow (in blue gems) and in other colors, weak to very weak tones of bodycolor

Dispersion

Strength: weak fire Value: 0.013

Comments

Apatite Chemistry & Crystallography

Chemical Name

calcium phosphate with fluorine, chlorine or hydroxyl group

Chemical Formula

Ca5(PO4)3(F,OH,Cl)

Synthesis

Crystal System

Hexagonal

Classification

Phosphate

Nature

Natural

Crystallinity

Crystalline

Comments

Apatite Characteristic Physical Properties

Hardness

5

Streak

White To Yellow-Gray

Specific Gravity

3.13-3.23 Range:+/- 0.05 Typical:3.18

Toughness

Fair

Inclusions

Apatite is a type II stone. The stones are often found with natural inclusions, healing cracks and hollow tubes.

Luster

Vitreous

Stability

Fair

Fracture

Conchoidal, Uneven

Cleavage

Poor, in two directions

Comments

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