Cobaltocalcite

Object/Artifact

-

Crater Rock Museum

Name/Title

Cobaltocalcite

Entry/Object ID

2014.1.56

Description

Chemical Composition: Al(OH)3 Crystal System: Hexagonal System Description: Common Name: Cobaltocalcite (Sphaerocobaltite) Chemistry: CaCO3 Group: Carbonates Location: Democratic Republic of Congo Description: Small specimen with one side having a pale pink crystalline structure. Matrix has some green areas with pale pinks throughout. Physical Charateristics: Color is red to pink. • Luster is vitreous. • Transparency crystals are transparent to translucent. • Crystal System is trigonal; bar 3 2/m • Crystal Habits include rhombohedrons and scalahedrons, but large crystals are rare. Often, any large crystals are sphaerocobaltite intergrown with calcite, coloring the whole crystal pink. Also botryoidal, globular, stalactitic and as crusts. • Cleavage is perfect in three directions, forming rhombohedrons. • Fracture is uneven. • Hardness is 4. • Specific Gravity is approximately 4.2 (above average for translucent minerals). • Streak is pale pink. • Associated Minerals are calcite, malachite, cobaltite and dolomite. • Other Characteristics: red or pink and white banding in massive forms and effervesces easily with dilute acids. • Notable Occurrences include Shaba, Zaire; Saxony Germany and from other secondary cobalt ore locations. • Best Field Indicators are color, crystal habit, reaction to acid, associations with cobalt ore deposits, and cleavage. 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

3-11/16 in

Width

1-1/2 in

Length

2-11/16 in

Location

Location

Display Case

FS-11

Room

Frieda Smith Hall

Building

Crater Rock Museum

Category

Permanent

Moved By

Ian Cunningham

Date

December 27, 2023