Orthoclase is a feldspar mineral containing K[AlSi3O8]. It is an important rock-forming mineral. It has a monoclinic crystal structure, and the crystals are columnar or blocky. Crystal twinning is common, and the aggregates are blocky, flaky or granular. The colour is white, colourless, light red, yellow, grey or green with white streaks. The diaphaneity ranges from transparent to translucent with a vitreous or pearly lustre. Its specific gravity is 2.55–2.63, and its Mohs hardness is 6–6.5. It has complete cleavage, uneven fractures and mainly forms in igneous and metamorphic rocks such as granite, pegmatite, rhyolite, trachyte, syenite, gneiss and schist.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsEditor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 Springer Nature Singapore Pte Ltd.
About this entry
Cite this entry
(2020). Orthoclase. In: Chen, A., Ng, Y., Zhang, E., Tian, M. (eds) Dictionary of Geotourism. Springer, Singapore. https://doi.org/10.1007/978-981-13-2538-0_1797
Download citation
DOI: https://doi.org/10.1007/978-981-13-2538-0_1797
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-2537-3
Online ISBN: 978-981-13-2538-0
eBook Packages: Earth and Environmental ScienceReference Module Physical and Materials ScienceReference Module Earth and Environmental Sciences