Name/Title
Garnet var. PyropeEntry/Object ID
LN2012.1.11Description
Chemical Composition: Mg3Al2(SiO4)3
Crystal System: Cubic or Isometric S
Description: Common Name: Garnet var. Pyrope
Chemistry: Mg3Al2(SiO4)3, Magnesium Aluminum Silicate
Group: Garnets
Location: unknown
Description: Deep red crystal in ovoid shape with large, planar surfaces..
PHYSICAL CHARACTERISTICS:
Color is red to reddish purple and sometimes a deep enough red to appear 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 common.
Cleavage is absent.
Fracture is conchoidal.
Hardness is 7 - 7.5
Specific Gravity is approximately 3.6 (above average for translucent minerals)
Streak is white.
Associated Minerals are olivine, serpentine, biotite, hornblende, augite, pyroxenes and diamond.
Other Characteristics: index of refraction is 1.73
Best Field Indicators are crystal habit, color, hardness and enviroment.
Fracture: conchoidal
Hardness: 7 Quartz
Luster: Vitreous
Occurrence: Garnets as a group are relatively common in highly metamorphosed rocks and in some igneous formations. They form under the high temperatures and/or pressures that those types of rocks must endure
Rock Type: Igneous
Specific Gravity: 3.8-4.3
Streak: white
Variety: Pyrope is the only garnet that is always a shade of red. Although less common than most other garnets, pyrope is a common gemstone. Pyrope is the only garnet whose most common source is igneous rather than metamorphic. Most pyrope comes from ultramafic igneous rocks that contain olivine and/or diamond. Metamorphic pyrope comes from the metamorphism of the igneous rocks previously mentioned or from magnesium rich rocks subjected to high grade metamorphism. Almandine and pyrope form a series in which iron substitutes for the magnesium in pyrope. In fact, pure pyrope is unknown in nature and the various proportions are referred to as pyrope-almandine mixes. one mixture of approximately two to one (pyrope to almandine) is a variety called rhodolite which has an attractive red-lavender color and is cut as a gemstone. Pyrope is difficult to distinguish from almandine but is usually clear and free from flaws, at least more so than almandine.Collection
Carol Swisher Mineral-Uses CollectionDimensions
Width
13/16 inDepth
1/2 inLength
7/8 inDimension Notes
Dimension taken at widest pointsLocation
Location
Container
front rowDrawer
rightShelf
topCabinet
Mineral UsesWall
westBuilding
Museum Entrance HallwayCategory
Permanent
