By Parent Géry (Own work) [CC-BY-SA-3.0], via Wikimedia Commons
An overview on Sapphirine Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sapphirine gems.
Sapphirine Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Sapphirine Information
| Data | Value |
| Name | Sapphirine |
| Crystallography | Monoclinic or triclinc; crystals tabular; usually granular or as disseminated grains. |
| Colors | Pale blue, bluish gray, greenish gray, green; depth of blue color varies with Fe. Also, (rarely) purplish pink. |
| Luster | Vitreous. |
| Hardness | 7.5. |
| Density | 3.4-3.5. |
| Birefringence | 0.006. |
| Cleavage | Lndistinct; fracture uneven to subconchoidal. |
| Stone Sizes | Facetable sapphirine is exceedingly rare, even though the material occurs in transparent grains. GIA noted a very unusual purplish-pink stone of 1.54 cts, oval, with included mica “book” (phlogopite), from Sri Lanka; R.l. =1.701—1.707; β= 1.705; birefringence = 0.006; S.G.: 3.51. The refractive indices of sapphirine are close to idocrase, but the former is biaxial. Other such gems exist but have been misidentified. |
| Luminescence | None reported. |
| Spectral | Not diagnostic. |
| Formula | Mg3,5Al9Si4,5O20 (+Fe). Complex substitution of Mg/Al/Si with charge balancing. Two polytypes: Sapphirine-2M = (Mg,Al)8(Al,Si)6O20; monoclinic. Sapphirine-Te=(Mg,Al )8(Al,Si)6O20; triclinic. |
| Pleochroism | Distinct: X = pinkish buff; yellowish; pale smoky brown; colorless: Y=sky blue: sapphire blue: greenish blue; Z=dark sky blue; sapphire blue. |
Optics: a =1.714-1.716; β= 1.719-1.721; γ= 1.720-1.723.
Biaxial (—).
Occurrence: In mineral veins or cavities in eruptive igneous rocks.
Milford, Utah; Keweenaw Peninsula, Michigan; Lake Superior, Minnesota.
Canada; Scotland; England: Sweden; Czechoslovakia;
Japan; South Africa; Greenland; Madagascar: Italy: Sri Lanka.
Name: In allusion to the (sapphire blue) color.
