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MINERAL NAME, FORMULA | |
| RED, REDDISH BROWN, BLACK color; equant crystals, often showing 12 to 24 faces; may show parting that may be confused with cleavage; can be massive; H=6.5-7.5. | GARNET,
(Fe,Mg,Ca)3Al2Si3O12 |
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| DARK to LIGHT GRAY, but can be any color including purple, pink, yellow, etc. CONCHOIDAL FRACTURE; vitreous luster; H=7; may have crystal faces. | QUARTZ,
SiO2 |
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| GREEN, brown, yellow color; vitreous luster; GENERALLY GRANULAR; heavy; H=6. | OLIVINE,
(Mg,Fe)2SiO4 |
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