Orientite

Formula: Ca₂MnMn₂Si₃O₁₀(OH)₄

Origin of name: after locality Oriente Province, Cuba

Crystal system: orthorhombic

Crystal class: mm2

Twinning: 

Unit cell: 

Colour: light brown, deep red-brown to almost black

Diaphaneity: 

Luster: resinous to subvitreous

Habit: crystals prismatic tabular, to 1 mm

Hardness: 4.5 to 5

Specific gravity: 3.05

Cleavage: 2; {001} and {120} imperfect

Tenacity: 

Streak: brown

Synonyms/varieties:

Comments: