Margarite

Availability

Sold

Size

8 x 7 x 3 cm - Sm Cabinet 

Formula

CaAl₂(Si₂Al₂)O₁₀(OH)₂ (RRUFF)

Locality

Chester Emery mines, Hampden Co., Massachusetts, United States

Large pale pink micaceous crystals to 1.5cm sandwiched between chloritic schists. Excellent specimen.

Margarite is a phyllosilicate - and  a mica group member. It is defined as dioctahedral brittle mica. Aluminum occupies the (M) octahedral positions with possible subsitutes of lithium, calcium (or possibly Na) at the Interlayer spots, and hydroxyl at the (A) positions. Be and Al can replace Si at the (T) positions. For more information on Mica minerals and other phyllosilicates please reference our article - Click Here.

Large crystals of Margarite are rare. The mineral usually forms scaly or platy aggregates. Margarite typically occurs with diaspore in contact metamorphic deposits (Bernard & Hrysl), also in chlorite schists (Mindat). It is usually occurs associated with corundum, diaspore, tourmaline, staurolite, glauphane, chlorite, and magnetite...in high aluminum deposits (Handbook of Min.).