Colemanite

Object/Artifact

-

Crater Rock Museum

Name/Title

Colemanite

Entry/Object ID

2004.1.140

Description

Chemical Composition: CaB3O4(OH)3-H2O Crystal System: Monoclinic System Description: Common Name: Colemanite Group Name: Chemistry: CaB3O4(OH)3-H2O Location: Billie Mine, Death Valley, CA Description: 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. Associated Minerals are calcite, celestite, borax, ulexite, kernite, hydroboracite and other borate minerals. Other Characteristics: exfoliates (peels off) upon heating. Best Field Indicators are crystal habit, associations, locality, density, cleavage and hardness. Fracture: uneven Hardness: 4 Flourite Luster: Vitreous Occurrence: Notable Occurrences include Yermo, Boron, Death Valley and other California localities, USA; Nevada, USA; Chile and Panderma, Turkey. Colemanite is a borate mineral found in evaporite deposits of alkaline lacustrine environments. Colemanite is a secondary mineral that forms by alteration of borax and ulexite. Specific Gravity: 2.4 Streak: white

Collection

Suomynona Mineral Collection

Acquisition

Accession

2004.1

Source or Donor

Suomynona Mineral Collection

Acquisition Method

Donation

Dimensions

Width

2-1/2 in

Depth

2 in

Length

4-1/2 in

Dimension Notes

Dimension taken at widest points

Location

Location

* Untyped Location

Mentzer Hall, MH-11

Category

Exhibit

Moved By

Jillian Mather Kettley

Date

September 12, 2025

Notes

Location added when performing inventory

Location

Room

Neil Johnson

Building

Attic Storage

Category

Permanent

Moved By

Lehman R.

Date

August 28, 2009