Stevensite

Formula: Ca_0.15Mg₃Si₄O₁₀(OH)₂.nH₂O

Origin of name: for Stevens Institute, Hoboken, New Jersey, USA

Crystal system: monoclinic

Crystal class: unknown

Twinning:

Unit cell: 

Colour: pink, buff, amber

Diaphaneity: translucent

Luster: dull to resinous

Habit: massive, fine-grained

Hardness: 2.5

Specific gravity: 2.15 to 2.57

Cleavage: 1; {001} perfect

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: member of the smectite group (clay)