Coesite

Formula:  SiO₂

Origin of name:  For Loring Coes, Jr. American chemist

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell:

Colour:  Colourless

Diaphaneity:  Transparent

Luster:  Vitreous

Habit:  Microscopic irregular grains

Hardness:  7.5 (approximate)

Specific gravity:  2.93

Cleavage:  None

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Polymorphous with cristobalite, quartz, tridymite and stishovite