Name/Title
MicroclineEntry/Object ID
2009.62.143Description
Chemical Composition: .
Crystal System: Triclinic System
Description: Common Name: Microcline
Chemistry: KAlSi3 O8 , Potassium aluminum silicate.
Group: Feldspars
Location: Minas Gerias, Brazil
Description: Angular, porus, beige to dull pink in color with small black crystal in some areas.
PHYSICAL CHARACTERISTICS:
Color is usually off-white,yellowish, flesh pink, brown or green.
Luster is vitreous to sometimes pearly or dull if weathered.
Transparency crystals are translucent, but usually translucent to opaque.
Crystal System is triclinic; bar 1
Crystal Habits include blocky, or tabular crystals. Crystals have a nearly rectangular or square cross-section with slightly slanted dome and pinacoid terminations. Twinning is common. Crystals can be twinned according to the Albite, Pericline, Carlsbad, Manebach and Baveno laws. Microcline can be found as a major rock forming component in granites, syenites and in metamorphic gneisses.
Cleavage is perfect in one and good in another direction forming nearly right angled prisms.
Fracture is conchoidal.
Hardness is 6 - 6.5.
Specific Gravity is approximately 2.5 (average)
Streak is white.
Associated Minerals are quartz, muscovite and plagioclase feldspars.
Other Characteristics: Lamellar twinning may cause a grooved effect on cystal and cleavage surfaces that appear as striations. Perthite intergrowths causes a stripped appearance is some specimens.
Best Field Indicators are occurence, twinning, color and luster.
Fracture: Conchoidal
Hardness: 6 Orthoclase
Luster: Vitreous
Occurrence: Notable Occurrences include Pikes Peak region of Colorado and North Carolina among other sites in the USA; Russia; Norway and Madagascar.
Rock Type: Igneous
Specific Gravity: 2.61
Streak: white
Variety: Amazonite is a variety that is deep green and is suitable for carving and polishing. The perthite variety is a stripped, veined or almost zebra patterened stone, that is produced from lamellar intergrowths inside the crystal.Collection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationLocation
Category
ExhibitDate
June 11, 2024Location
* Untyped Location
Needs Updated Location - 2022Category
PermanentMoved By
Scott LonganDate
September 26, 2009