Name/Title
GrossulariteEntry/Object ID
2014.1.18Description
Chemical Composition: Al(OH)3
Crystal System: Hexagonal System
Description: Common Name: Grossularite
Chemistry: Ca3Al2(SiO4)3
Group: Silicates
Location: Riddle, Oregon
Description: Many small crystals with some small cavities. Color is dull green to gray.
Physical Charateristics:
•Color is colorless, yellow, orange, green, red, grey and black.
•Luster is vitreous.
•Transparency crystals are transparent to translucent.
•Crystal System is isometric; 4/m bar 3 2/m
•Crystal Habits include the typical rhombic dodecahedron. also seen is the 24 sided trapezohedron. Combinations of these forms are common and sometimes the rare faces of the hexoctahedron, a 48 sided crystal habit that rarely is seen by itself, can also combine with these other forms making very attractive, complex and multifaceted crystals. Massive and granular occurrences are also seen. Commonly forms crusts that show many rhombic faces
•Cleavage is absent.
•Fracture is conchoidal.
•Hardness is 6.5 - 7
•Specific Gravity is approximately 3.5+ (above average for translucent minerals).
•Streak is white.
•Associated Minerals are micas, chlorite, diopside, calcite, idocrase and serpentine.
•Other Characteristics: index of refraction is 1.75 and many faces show a sort of striation caused by multiple crystal forms.
•Notable Occurrences are Asbestos, Canada; Mexico; Kenya; Italy and Sri Lanka.
•Best Field Indicators are crystal habit, color, environment and hardness.
Hardness: 7 Quartz
Rock Type: SedimentaryCollection
RAGM Mineral CollectionAcquisition
Accession
2014.1Source or Donor
Crater Rock Museum (unknown donors)Acquisition Method
GiftDimensions
Height
2-1/2 inWidth
2-1/4 inLength
1-1/4 inLocation
Location
Shelf
CS-I-1Room
Curation StorageBuilding
Crater Rock MuseumDate
February 3, 2024Location
Shelf
4th shelfCabinet
Case# 20Wall
WestBuilding
Freida Smith HallCategory
Permanent
