Almandine with Muscovite

Sample of a reddish brown euhedral dodecahedral Almandine crystal coated with flaky white Muscovite with a pearly lustre. Almandine (Fe2+3Al2Si3O12) is iron-rich aluminum silicate part of the Garnet group. Almandine can be deep red to brown or brownish black and has a vitreous lustre. Streak is colourless and hardness is 6 1/2 to 7 1/2. Almandine usually occurs as dodecahedrons or trapezohedrons but can also be granular, lamellar, compact or disseminated. Muscovite (KAl3Si3O10(OH)2) can be white, colourless, yellowish, greenish, pink, brownish or multicoloured. Lustre is vitreous or pearly and streak is colourless. Hardness is 2 to 2 1/2 and cleavage is perfect in one direction. Muscovite usually occurs as tabular crystals that are parallel to the cleavage and have a hexagonal outline but can also be foliated, flaky, fine scaly or fibrous.