Colemanite

Object/Artifact

-

Crater Rock Museum

Colemanite

Colemanite

Name/Title

Colemanite

Entry/Object ID

2014.1.34

Description

Chemical Composition: Al(OH)3 Crystal System: Hexagonal System Description: Common Name: Colemanite Chemistry: CaB3O4(OH)3-H2O Group: Carbonates Location: Boron, California Description: Small specimen with distinct linear and beveled crystals. Color is white. Physical Charateristics: •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. •Associated Minerals are calcite, celestite, borax, ulexite, kernite, hydroboracite and other borate minerals. •Other Characteristics: exfoliates (peels off) upon heating. •Notable Occurrences include Yermo, Boron, Death Valley and other California localities, USA; Nevada, USA; Chile and Panderma, Turkey. •Best Field Indicators are crystal habit, associations, locality, density, cleavage and hardness Hardness: 7 Quartz Rock Type: Sedimentary

Collection

RAGM Mineral Collection

Acquisition

Accession

2014.1

Source or Donor

Crater Rock Museum (unknown donors)

Acquisition Method

Gift

Dimensions

Height

2-1/4 in

Width

1-3/8 in

Length

1-3/8 in

Location

Location

Display Case

FS-11

Room

Frieda Smith Hall

Building

Crater Rock Museum

Category

Permanent

Moved By

Curtis Gardner

Date

December 27, 2023