Name/Title
MargariteEntry/Object ID
2014.1.33Description
Chemical Composition: Al(OH)3
Crystal System: Hexagonal System
Description: Common Name: Margarite
Chemistry: CaAl2(Al2Si2O10)(OH)2
Group: Mica Group
Location: Unknown
Description: Small specimen with distinct linear and beveled crystals. Color is lavender.
Physical Charateristics:
Color is a bright scarlet or cinnamon red to a brick red.
•Luster is adamantine to submetallic in darker specimens.
•Transparency crystals are translucent to transparent.
•Crystal System is trigonal; 32
•Crystal Habits: individual, well formed, large crystals are scarce; crusts and crystal complexes are more common; may be massive, or in capilary needles. Crystals that are found tend to be the six sided trigonal scalahedrons that appear to have opposing three sided pyramids. It also forms modified rhombohedrons, prismatic and twinned crystals as discribed above.
•Cleavage is perfect in three directions, forming prisms.
•Fracture is uneven to splintery.
•Hardness is 2 - 2.5.
•Specific Gravity is approximately 8.1+ (very heavy for a non-metallic mineral)
•Streak is red
•Associated Minerals are realgar, pyrite, dolomite, quartz, stibnite and mercury.
•Other Characteristics: silghtly sectile and crystals can be striated.
•Notable Occurances include Almaden, Spain; Idria, Serbia; Hunan Prov., China and California, Oregon, Texas, and Arkansas, USA.
•Best Field Indicators are crystal habit, density, cleavage, softness and color.
Hardness: 7 Quartz
Rock Type: SedimentaryCollection
RAGM Mineral CollectionAcquisition
Accession
2014.1Source or Donor
Crater Rock Museum (unknown donors)Acquisition Method
GiftDimensions
Height
2-3/4 inWidth
2 inLength
1-3/4 inLocation
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023Location
Shelf
2nd shelfCabinet
Case# 20Wall
WestBuilding
Freida Smith HallCategory
Permanent
