Nice hand sample of schist from the Snake Range in Nevada.
Schist is a foliated metamorphic rock that forms from the alteration of existing rock. In this case, the protolith (parent rock) was likely pelitic, like a shale or mudstone. This beautifully foliated rock has a great micaceous sheen, and some great idioblastic (euhedral, or well-shaped) garnets. This is chlorite-garnet-muscovite schist; other rocks in the area have staurolite, as well, but this is within the cholorite isograd (set of temperature-pressure conditions where a mineral is stable). 1.6 oz.
This would be a great gift for the budding geologist or scientist.
You will receive the pictured specimen.