Name/Title
ColemaniteEntry/Object ID
2009.62.200Description
Chemical Composition: CaB304(OH)3-H2O
Crystal System: Monoclinic System
Description: Chemistry: CaB3O4(OH)3-H2O, Hydrated Calcium Borate Hydroxide
Class: Carbonates
Subclass: Borates
PHYSICAL CHARACTERISTICS:
Color is white to clear.
Luster is vitreous.
Transparency crystals are transparent to translucent.
Crystal System is monoclinic; 2/m
Crystal Habits are quite variable, but include the short prismatic crystals always with complicated facets. Equant crystals that appear stubby and bead-like are also common. The crystals are sometimes flattened and can appear bladed. The terminations are either blunted or steeply pyramidal. Also massive, lamellar and granular habits are found.
Cleavage is perfect in one direction and distinct in another.
Fracture is uneven.
Hardness is 4.5
Specific Gravity is approximately 2.4 (somewhat lower than average)
Streak is white.
Best Field Indicators are crystal habit, associations, locality, density, cleavage and hardness.
Fracture: Uneven
Hardness: 4 Fluorite
Luster: Vitreous
Occurrence: Notable Occurrences include Yermo, Boron, Death Valley and other California localities, USA; Nevada, USA; Chile and Panderma, Turkey.
Rock Type: Sedimentary
Specific Gravity: 2.4
Streak: White
Variety: Colemanite, like other borates, is a complex mineral, that is found in playa lakes and other evaporite deposits. The basic structure of colemanite contains endless chains of interlocking BO2(OH) triangles and BO3(OH) tetrahedrons with the calciums, water molecules and extra hydroxides interspersed between the chains.Collection
RAGM Mineral CollectionDimensions
Width
6 inDepth
4 inLength
6 inLocation
Location
Display Case
FS-9Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentDate
August 8, 2023
