Corundum var. Ruby in Zoisite

Object/Artifact

Crater Rock Museum

Name/Title

Corundum var. Ruby in Zoisite

Entry/Object ID

2014.1.27

Description

Chemical Composition: Al(OH)3 Crystal System: Hexagonal System Description: Common Name: Corundum Chemistry: Al2O3 Group: Oxides and Hydroxides Location: Blue Ridge Mtns., North Carolina Description: Relatively flat specimen colored primarily in lime green with ruby red patches and some black spotting throughout. Physical Characteristics: •Color is highly variable. The color can be white or colorless, blue, red, yellow, green, brown, purple, and pink; there are also instances of color zonation. •Luster is vitreous to adamantine. •Transparency: Crystals are transparent to translucent. •Crystal System is trigonal; bar 3 2/m •Crystal Habits include sapphire's typical six-sided barrel shape that may taper into a pyramid, and ruby's hexagonal prisms and blades. •Cleavage is absent, although there is parting which occurs in three directions. •Fracture is conchoidal. •Hardness is 9 •Specific Gravity is approximately 4.0+ (above average for translucent minerals) •Streak is white. •Associated Minerals include calcite, zoisite, feldspars, micas and garnets. •Other Characteristics: Refractive index is around 1.77; pleochroic (meaning color intensity is variable from different viewing directions); striations on parting surfaces. •Notable Occurrences include Burma; Sri Lanka; North Carolina and Montana, USA; many African localities; several localities in India, and Middle Eastern and Southeast Asian countries. •Best Field Indicators are extreme hardness, density and crystal habit. 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

3-3/4 in

Width

3/4 in

Length

2-3/8 in

Location

Display Case

FS-11

Room

Frieda Smith Hall

Building

Crater Rock Museum

Date

July 22, 2023