Difference between revisions of "Scapolite"
From The Gemology Project
m (→Tenebrescence) |
m |
||
Line 5: | Line 5: | ||
===Tenebrescence=== | ===Tenebrescence=== | ||
− | A fairly recent find (2005) in Badakhshan, Afghanistan is tenebrescent scapolite. This colorless to silvery material is unearthed near the hackmanite deposits and shows an aquamarine color after exposure to | + | A fairly recent find (2005) in Badakhshan, Afghanistan is tenebrescent scapolite. This colorless to silvery material is unearthed near the hackmanite deposits and shows an aquamarine color after exposure to SWUV light. The intensity of this color (blue) depends on the time it has been exposed to the UV lightning. |
− | Exposure to an UVP UVG4 | + | Exposure to an UVP UVG4 SWUV lamp for 15 minutes triggered an almost Santa Maria aquamarine blue color that faded gradually during the following 2-3 minutes in natural daylight. |
Revision as of 20:30, 23 December 2006
Scapolite | |
---|---|
Chemical composition | Complex sodium aluminium silicate |
Crystal system | Tetragonal |
Habit | Prismatic and massive |
Cleavage | Distinct to perfect (depending on direction) |
Fracture | Conchoidal |
Hardness | 6 |
Optic nature | Uniaxial - |
Refractive index | 1.545-1.580 (depending on color) |
Birefringence | 0.016-0.02 |
Dispersion | Low, 0.017 |
Specific gravity | 2.634-2.74 (depending on color) |
Lustre | Vitreous |
Pleochroism | Medium to strong (depending on color) |
Optical properties
Tenebrescence
A fairly recent find (2005) in Badakhshan, Afghanistan is tenebrescent scapolite. This colorless to silvery material is unearthed near the hackmanite deposits and shows an aquamarine color after exposure to SWUV light. The intensity of this color (blue) depends on the time it has been exposed to the UV lightning. Exposure to an UVP UVG4 SWUV lamp for 15 minutes triggered an almost Santa Maria aquamarine blue color that faded gradually during the following 2-3 minutes in natural daylight.