Almandine
Chemical Formula: Fe₃Al₂Si₃O₁₂
Chemical Composition: Aluminum, Iron, Silicon, Oxygen
Crystal System: Cubic (isometeric)
Class: Silicates
Mineral Group: Garnet
Crystal Habit: Trapezohedral, dodocahedral
Hardness: 7 — 7.5
Density/Specific Gravity: 3.93 — 4.30
Refractive Index: 1.770 — 1.820
Double Refraction: None
Dispersion: 0.027
Absorption Spectra: 617, 576, 526, 505, 476, 462, 438, 428, 404, 393
Colour: Brownish red, red, blackish red, red with violet tint
Pleochroism: None
Transparency: Transparent to translucent
Lustre: Vitreous (glass like appearance)
Luminescence: Inert
Cleavage: None
Fracture: Irregular/uneven
Assigned Planet: Pluto
Additional Zodiac Stone: Leo
Countries: Deposits found in Austria, Brazil, Czech Republic, India, Magagascar, Sri Lanka, Tanzania, USA, Zambia, Zimbabwe
Notes: There are more Almandine gemstones faceted and used in jewellery than any other gemstone categorised in the garnet group

Attribution: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons