fluorapatite
Fluorapatite, a member of the Apatite group and often known simply by that name, is a captivating gemstone species that derives its name from the Greek word "apatein," meaning to deceive, owing to its often misleading similarity to other more valuable gemstones. Comprising calcium phosphate, the Apatite group occur in a spectrum of colours, with the fluorapatite variety being one of the most prized for its transparent, vivid hues.
Geologically, fluorapatite is commonly found in igneous rocks, sedimentary deposits, and metamorphic environments. Notable sources include Brazil, Mexico, and Madagascar. Its chemical composition lends it a remarkable resilience, making it an excellent choice for jewellery.
One intriguing aspect of fluorapatite is its potential for fluorescence, emitting a captivating glow when exposed to ultraviolet light. This property has earned it a special place in scientific research, where it is used in geological dating techniques and the study of minerals.
Fluorapatite continues to be valued for its versatility, vibrant colours, and unique properties, making it a cherished gemstone in jewellery design and a valuable mineral in various scientific disciplines.
Click on the terms in the table below to discover their meaning
Click on the terms in the table below to discover their meaning
| Name | Fluorapatite |
|---|---|
| Category |
Phosphate mineral |
| Chemical Formula |
Ca5 |
| IMA Symbol | Fap |
| Crystal System | Hexagonal |
| Crystal Habit | Prismatic to tabular; also granular, globular to reniform, nodular, massive |
| Twinning | Rare as contact twins |
| Cleavage | Poor |
| Fracture | Conchoidal to uneven |
| Tenacity | Brittle |
| Hardness (Moh's Scale) |
5 (defining mineral) |
| Specific Gravity | 2.55 - 2.63 |
| Diaphaneity | Transparent to translucent |
| Colour | Sea-green, violet, purple, blue, pink, yellow, brown, white, colourless, may be zoned; colourless or faintly tinted in thin section |
| Streak | White |
| Lustre | Vitreous to subresinous |
| Optical Class | Uniaxial (-) |
| Refractive index | nω = 1.631 - 1.650 |
| nε = 1.627 – 1.646 | |
| Birefringence | δ = 0.002 – 0.008 |
| Dispersion | Rd = 0.013 |
| Pleochroism | Weak to strong if coloured |
| Clarity | Type II |
| Notable Varieties | Blue Apatite, Yellow Apatite |
References
Mineralogical Society of America. (2005). Fluorapatite. In J. W. Anthony, R. A. Bideaux, K. W. Bladh, & M. C. Nichols (Eds.), Handbook of Mineralogy. Chantilly, VA 20151-1110, USA: Mineralogical Society of America. Retrieved from https://
The Gemology Project. (2012, August 13). Apatite. Retrieved from The Gemology Project: http://
