Bournonite

Object/Artifact

-

Crater Rock Museum

Name/Title

Bournonite

Entry/Object ID

2014.1.25

Description

Chemical Composition: Al(OH)3 Crystal System: Hexagonal System Description: Common Name: Bournonite Chemistry: CuPbSbS3 Group: Sulfides Location: Unknown Description: Small specimen with gray crystals in a non-symmetrical bunching. Physical Charateristics: •Color is silver gray or black. •Luster is metallic. •Transparency crystals are opaque. •Crystal System is orthorhombic; 2/m2/m2/m •Crystal Habits include tabular to prismatic crystals. Twinning is common and if repeated forms flat wheel shaped crystals called cog wheels. Also massive and granular. •Cleavage is poor in one direction. •Fracture is subconchoidal. •Hardness is 2.5 - 3 •Specific Gravity is approximately 5.8 (above average for metallic minerals) •Streak is black. •Associated Minerals are siderite, fluorite, galena, sphalerite, calcite and pyrite. •Other Characteristics: although the luster can be bright, bournonite develops a dull tarnish. Crystals are usually striated on their sides which produces the "teeth" of the cog wheel. •Notable Occurrences include England; California, USA; Mexico; Peru and Australia. •Best Field Indicators are crystal habit (especially twinning), color and density. 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

2-1/8 in

Width

1 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