Difference between revisions of "Almandine"
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==Diagnostics== | ==Diagnostics== | ||
+ | [[File:Almandine.jpg|thumb|left|300px|Oval, faceted Almandine garnet ]]<br clear="left" /> | ||
===Color=== | ===Color=== | ||
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Almandine has a typical iron spectrum | Almandine has a typical iron spectrum | ||
+ | [[File:Almandine_spectrum.jpg|thumb|left|240px]]<br clear="left" /> | ||
===Inclusions=== | ===Inclusions=== | ||
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===Specific gravity=== | ===Specific gravity=== | ||
− | + | Almandine sinks in all common heavy liquids. | |
===Optical effects=== | ===Optical effects=== | ||
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===Rhodolite=== | ===Rhodolite=== | ||
+ | [[File:Rhodolite_Garnet_7.jpg|left|thumb|300px|Faceted Rhodolite Garnet <br /> Photo courtesy of Rick Martin]]<br clear="left" /> | ||
+ | Rhodolite is the purple (pinkish/violet) variety of pyrope-almandine. | ||
+ | <br clear="left" /> | ||
− | + | ==Inclusions== | |
+ | [[Image:Sk_garnet_silk.jpg|thumb|left|240px|Silk, crystals, and a crystal looking like a skull, inside of a pyrope-almandine garnet.<br />~85X Magnification<br /> ©Jamey Swisher]] | ||
+ | <br clear="left" /> | ||
==Localities== | ==Localities== | ||
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India, USA, Brazil | India, USA, Brazil | ||
− | == | + | ==Occurrence== |
Metamorphic rocks | Metamorphic rocks |
Latest revision as of 18:33, 2 December 2012
Almandine Garnet | |
---|---|
Chemical composition | Fe3Al2(SiO4)3
Iron aluminum silicate |
Crystal system | Cubic |
Habit | Dodecahedra |
Cleavage | None |
Hardness | 7.5 |
Optic nature | Isotropic |
Refractive index | 1.78-1.81 |
Birefringence | None |
Specific gravity | 3.95 - 4.20 |
Lustre | Vitreous |
Contents
Diagnostics
Color
Brownish red, red to violet/purple
Spectroscope
Almandine has a typical iron spectrum
Inclusions
- Short rutile needles in 3 directions
- Crystals surrounded by stress cracks
- Irregular and rounded crystals
Polariscope
Almandine is isotropic but may have a small DR.
Specific gravity
Almandine sinks in all common heavy liquids.
Optical effects
Almandine may show asterism and chatoyancy
Varieties
Rhodolite
Rhodolite is the purple (pinkish/violet) variety of pyrope-almandine.
Inclusions
Localities
India, USA, Brazil
Occurrence
Metamorphic rocks