Ulexite (TV Rock)
Image: Andrew Silver (Public domain)
Mineral NameUlexite (TV Rock)
Chemical FormulaNaCaB5O9·8H2O
Mohs Hardness2.5
Crystal Systemtriclinic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {010}, good on {110}
Fractureuneven
Specific Gravity1.96
Colorswhite, colorless, grayish
Transparencytransparent
Type LocalityBorax Mine, Boron, California
Mineral Groupborates
Usescollector, optical demonstrations, source of boron
Associated Mineralsborax, kernite, colemanite, gypsum
Raritycommon
Description
The image displays several blocky, white to off-white specimens of ulexite, characterized by a distinct fibrous texture that allows for its unique 'TV rock' optical effect. The surfaces appear somewhat dull or silky.
Geological Context
Ulexite is an evaporite mineral found in arid regions, forming in playa lakes and saline basins where boron-rich brines precipitate various borate minerals. It is typically associated with other borates and evaporite minerals.
