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Afghanite is a rare and coveted mineral with a striking blue color, first identified in 1968. With a very close resemblance to Lazurite, and occurring together in the same deposits, Afghanite is distinguished by its unique crystal habit. Afghanite is named after its most significant locality in northern Afghanistan. |
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Chemical Formula |
(Na,Ca,K)8Al6Si6O24(Cl2,SO4,CO3)3 · 0.5H2O |
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Composition |
Hydrous silicate of sodium, calcium, and potassium, with chloride, carbonate, and sulfate radicals
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Color |
Light to dark blue. Microcrystals from Italy may be be white, colorless, or light yellow. |
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Streak |
White |
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Hardness |
5.5 - 6 |
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Crystal System |
Hexagonal |
Crystal Forms
and Aggregates |
In wide or elongated prismatic crystals with partial or stepped pyramidal terminations. Occasionally doubly terminated as bypyramidal crystals. Also as distorted crystal groups, as tabular microcrystals, grainy, and encrusting.
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Transparency |
Translucent to Opaque |
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Specific Gravity |
2.5 - 2.6 |
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Luster |
Vitreous |
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Cleavage |
1, All |
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Fracture |
Conchoidal to uneven |
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Tenacity |
Brittle |
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Other ID Marks |
Often fluorescent yellow to orange in longwave ultraviolet light. |
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In Group |
Silicates; Tectosilicates; Feldspathoid Group |
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Striking Features |
Color, crystal habit, and locality |
| Environment |
In Lazurite veins in metamorphosed limestones.
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| Rock Type |
Metamorphic |
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Popularity (1-4)
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3 |
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Prevalence (1-3)
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3 |
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Demand (1-3) |
2 |
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Afghanite is strictly used as a rare collectors mineral.
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Afghanite is a rare mineral, with the only significantly important deposit being Sar-e Sang, Kokcha Valley, in Badakshan Province,
Afghanistan, where it forms large and beautiful crystals that are almost always embedded on a white marble matrix. Small crusts of Afghanite occur in the vicinity of Slyudyanka, near the southern area of Lake Baikal, and white and colorless microcrystals in the vicinity of Vico Lake, near Viterbo, Italy.
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Lazurite - Forms in different crystals; has blue streak and poor cleavage.
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We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.
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