AXINITE: Baja California, Mexico (~2.0, rough 1½ inches long)
Cut axinites are usually intensely trichroic, with the brown and purple colors dominating. The material is exquisite but is almost never completely free of flaws and feathers. Axinite is actually an extremely rare cut gem and could be on the most magnificent because of its rich colors and brilliance. Clean stones over 5 carats are difficult to find and worthy of museum display. Axinite is hard enough to be worn in jewelry, though it is a bit brittle.
Axinite Value
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Axinite Information
| Data | Value |
| Name | Axinite |
| Varieties | Ferro-axinite, Magnesio-axinite, Manganaxinite |
| Crystallography | Triclinic. Distinctive wedge-shaped crystals; also tabular |
| Refractive Index | 1.674 - 1.704 |
| Colors | Violet-brown, colorless, yellowish (Mn), pale violet to reddish (Mn), blue (Mg). |
| Luster | Vitreous |
| Hardness | 6.5 - 7, variable with direction |
| Specific Gravity | 6.5 - 7 |
| Density | 3.26 -3.36; magnesioaxinite = 3.18 |
| Birefringence | 0.010-0.012 |
| Cleavage | Good 1 direction. Fracture uneven to conchoidal. Brittle. |
| Dispersion | Large |
| Stone Sizes | Axinite is rare faceted gems over 10 carats. Material from Baja California will yield gems to 25 carats, but most stones, if clean, are less than 5 carats. SI: 23.6 (brown, Mexico) PC: 16.5 (Baj, California) Geol. Mus., London: 0.78 (magnesioaxinite, Tanzania) |
| Heat Sensitivity | Slight |
| Luminescence | Red in SW (Franklin, New Jersey). Dull red in SW, orange-red in LW (Tanzania: magnesioaxinite). |
| Spectral | Narrow line at 5120, broad lines at 4920 and 4660, also at 4150. Sometimes lines visible at 5320, 4440, and 4150 (latter may be strong). |
| Wearability | * Very Good |
| Enhancements | None |
| Special Care Instructions | Avoid rough handling |
| Formula | (Ca, Mn, Fe, Mg)3Al2BSi4O15(OH) +Mg = magnesioaxinite If Fe > Mn = ferroaxinite If Mn> Fe = manganaxinite If Mn> Fe and Ca<1.5 = tinzenite |
| Pleochroism | Intense in all colored varieties: cinnamon brown/ violet-blue/ olive green, yellow, or colorless. Luning, Nevada: pale brown to colorless/deep brown/ brownish red. Pale blue/ pale violet / pale gray (magnesioaxinite) Sri Lanka: reddish-brown/dark violet/ colorless-yellowish. |
OPTICS: α= 1.674 – 1.693; β = 1.681 – 1.701 γ = 1.684 -1.704
Magnesioaxinite: α= 1.656; β = 1.660; γ = 1.668
Biaxial (-), 2V = 63-80° more
OCCURRENCE: Axinite is found in areas of contact metamorphism and metasomatism.
Yuba County, California: gemmy crystals. Also gem material from Coarse Gold, Madera County, California: New Melones, Calaveras County, California: Sri Lanka: feroaxinite, cinnamon-brown (indices = 1.675/1.681/1.685, birefringence = 0.010,S.G. = 3.31).
Luning, Nevada: masses
Pennsylvania; New Jersey.
Cornwall, England; Germany; Norway; Finland; USSR; Japan; Baja, California, Mexico, Tasmania.
Bourg d’Oisans, France: S.G. 3.28, R.I. = 1.68-1.69, in pockets in schist.
Switzerland: tinzenite
Tanzanite: magnesioaxinite
COMMENTS: Cut axinites are usually intensely trichroic, with the brown and purple colors dominating. The material is exquisite but is almost never completely free of flaws and feathers. Axinite is actually an extremely rare cut gem and could be on the most magnificent because of its rich colors and brilliance. Clean stones over 5 carats are difficult to find and worthy of museum display. Axinite is hard enough to be worn in jewelry, though it is a bit brittle.
Name: From a Greek word meaning axe, an allusion to characteristic crystal shape.
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