Name/Title
MicroclineEntry/Object ID
2009.62.153Description
Description: Common Name: Microcline
Chemistry: KAlSi3 O8 , Potassium aluminum silicate.
Class: Silicates
Location: Colorado
Description: Small angular single crystal, blue-green in color with smooth faces.
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.
Occurrence: Notable Occurrences include Pikes Peak region of Colorado and North Carolina among other sites in the USA; Russia; Norway and Madagascar.
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
ExhibitMoved By
Steve MillerDate
February 9, 2010