peristerite

gemstone
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Share
Share to social media
URL
https://www.britannica.com/topic/peristerite
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites
Related Topics:
gemstone
plagioclase

peristerite, iridescent gemstone in the plagioclase (q.v.) series of feldspar minerals. The name (from Greek peristera, “pigeon”) refers to the resemblance of fine specimens such as those from Ontario and Quebec to the commonly iridescent feathers of a pigeon’s neck. In peristerite—usually a form of one of the sodium-rich varieties of plagioclase albite or oligoclase—the sodium aluminosilicate and calcium aluminosilicate that make up the mineral separate and form intergrowths of submicroscopic but distinct crystals of the two compounds. The iridescence probably arises from diffusion of light by adjoining areas of different optical properties, or from reflection and diffraction of the separating crystals of the two different substances.