Goethite

Object/Artifact

-

Crater Rock Museum

Name/Title

Goethite

Entry/Object ID

2014.1.66

Description

Chemical Composition: Al(OH)3 Crystal System: Hexagonal System Description: Common Name: Goethite Chemistry: FeO(OH), Group: Oxides Location: Newport Mine, Gogebic County, Michigan Description: Small specimen with a botryoidal texture copper colored intrusions throughout specimen. Physical Charateristics: Color is yellow, brown, brownish red to black. Sometimes tarnished with irridescent colors. • Luster is earthy to dull for massive forms and metallic for crystals. • Transparency crystals are opaque. • Crystal System is orthorhombic; 2/m 2/m 2/m • Crystal Habits include prismatic and platy crystals, massive and aggregate forms include internally radiating or fibrous; reniform, botryoidal and stalactitic. • Cleavage is perfect in one direction. • Fracture is uneven to splintery. • Hardness is 5-5.5 • Specific Gravity is variable at 3.3 to 4.3 (light for metallic minerals) • Streak is brown, brownish yellow to orange yellow. • Associated Minerals include a large list of minerals (particularly secondary deposit minerals). • Notable Occurences include many iron mines around the world; especially nice specimens come from England, Mexico, and the Lake Superior region in Michigan, USA. 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

3-3/8 in

Width

2 in

Length

3-1/8 in

Location

Location

Display Case

FS-11

Room

Frieda Smith Hall

Building

Crater Rock Museum

Category

Permanent

Moved By

Jillian Mather Kettley

Date

February 13, 2025

Notes

Location added