Strontiopyrochlore

Formula: Sr₂Nb₂(O,OH)₇

Origin of name: from strontium and pyrochlore

Crystal system: cubic

Crystal class: 4/m -3 2/m

Twinning: 

Unit cell: a = 10.53

Colour: pale yellow, some white to bluish gray on cleavage planes

Diaphaneity: translucent to opaque

Luster: Vitreous-resinous

Habit: octahedral crystals to 0.5 mm

Hardness: 4

Specific gravity: 3.80

Cleavage: none

Tenacity: 

Streak: White

Synonyms/varieties:

Comments: Sr analogue of pyrochlore