A Geoscience Digital Image Library

TitleOrthoclase with Quartz
DescriptionOrthoclase belongs to the Feldspar group. Orthoclase is a polymorph of other minerals that share the same chemistry, but have different crystal structures. Orthoclase is the main k-spar of granites and syenites that cooled moderately quickly. Twinning is common in all feldspars and Carlsbad twinning is more common in Orthoclase. Orthoclase comes from the Greek orthos meaning “right” and kalo meaning “I cleave” in allusion to the mineral's right angle of good cleavage.
PhotographerShannon Heinle. 2002-09-13.
CollectionUniversity of North Dakota Mineralogy Collection #1657.
Key wordsorthoclase, feldspar, twinning
Tech details380 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens.
GeoDIL number2912