Name/Title
Grossular "Raspberry" GarnetEntry/Object ID
2004.1.35Description
Assemblage Zone: pegmatite dikes
Chemical Composition: Ca3Al2(SiO4)3, Calcium Al
Crystal System: Cubic or Isometric S
Description: Common Name: Raspberry Garnet
Group Name: Garnets
Chemistry: Ca3Al2(SiO4)3, Calcium Aluminum Silicate
Location: Sierra, Mexico
Description: Light gray with rosey pink splotches.
PHYSICAL CHARACTERISTICS:
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 srtiation caused by multiple crystal forms.
Best Field Indicators are crystal habit, color, enviroment and hardness.
Fracture: conchoidal to uneven
Hardness: 6 Orthoclase
Luster: Glassy
Occurrence: Notable Occurrences are Asbestos, Canada; Mexico; Kenya; Italy and Sri Lanka
Rock Type: Igneous
Specific Gravity: 4.2
Streak: white
Variety: Grossular (also known as grossularite), like other garnets, forms rounded crystals with 12 rhombic or 24 trapezoidal faces or combinations of these and some other forms. This crystal habit is classic for the garnet minerals. Grossular is the calcium aluminum garnet and forms in contact or regional metamorphic enviroments as does andradite the calcium iron garnet. It is believed that these garnets form from the metamorphism of impure siliceous limestones. Grossular has many color possibilities and is probably the most colorful of the garnets. The orange variety is the most common and specimens of orange grossular crusts are prized by many collectors. Green variety is called tsavorite and is occassionally cut as a gem. Hessonite is a red variety of grossular and is also sometimes used as a gem.Collection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
4-1/2 inDepth
5 inLength
4 inWeight
1,086 gDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
DS-10Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
ExhibitMoved By
Ian C.Date
January 22, 2025Notes
World case installationLocation
Display Case
FS-4Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentDate
August 18, 2023