Jasper
Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and... Wikipedia
- Category: Mineral
- Formula, (repeating unit): SiO 2 (with varying impurities)
- Crystal system: Hexagonal
- Crystal class: Quartz (Chalcedony)
- Colour: Most commonly red, but may be yellow, brown, green or (rarely) blue
- Cleavage: Indiscernible
- Mohs scale hardness: 6.5–7
- Luster: Vitreous
- Diaphaneity: Opaque
- Specific gravity: 2.5–2.9
- Refractive index: 1.54–2.65
- Birefringence: 0.009
- Data source: DuckDuckGo