Marekanite

marekanite

[¦mär·ə¦ka‚nīt]
(geology)
Rounded to subangular obsidian bodies that occur in masses of perlite.

Marekanite

 

(named after the Marekanka River in the Sea of Okhotsk basin), a variety of rhyolitic volcanic glass which when struck breaks apart into characteristic small concentric botryoidal spheres that are iridescent on the surface. Marekanite consists of low-water obsidian inside and strongly hydrated glass (perlite) on the outside. Marekanite forms during incomplete secondary hydration of glass.