Uralborite

Formula: CaB₂O₂(OH)₄

Origin of name: after locality Ural Mountains, Russia and from composition

Crystal system: Monoclinic

Crystal class: 2/m

Twinning:

Unit cell: a = 6.881, b = 12.305, c = 9.791, β = 97.46°

Colour: Colourless

Diaphaneity: Transparent

Luster: Vitreous

Habit: crystals prismatic, 5 to 7 mm, in radiating fibrous aggregates

Hardness: about 4

Specific gravity: 2.58-2.60

Cleavage: 1; distinct parallel to elongation

Tenacity: 

Streak: White

Synonyms/varieties: 

Comments: dimorphous with vimsite, fluoresces violet in LW ultraviolet light