Identify any rockfrom a photo.

Pegmatitic granite

Granite/pegmatite; predominantly quartz (SiO₂), feldspar, and mica

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite rock; exact identification requires testing

Banded gneiss pebble

Gneiss, typically quartz–feldspar–mica bearing

Weathered metamorphic rock, possibly schist or gneiss

Indeterminate; likely quartz–feldspar–mica rock, potentially greenschist or gneiss

Weathered granite or granitic gneiss

Quartz–feldspar–mica granitoid; possible biotite granite or gneiss

Unidentified fine mineral/rock powder

Indeterminate from image; possibly crushed quartz-rich sand or finely milled rock

Chalcedony (likely carnelian or jasper)

Microcrystalline quartz, SiO₂; iron-bearing varieties produce red-orange colors

Mixed beach-stone and tumbled-glass collection

Predominantly uncertain rocks (likely basalt, granite, and quartz-bearing stones) with anthropogenic glass; one possible banded agate or jasper

Mica schist (likely biotite–muscovite schist)

Mica schist; chiefly quartz (SiO₂) plus muscovite and biotite mica, with possible garnet or graphite

Polished green-and-black banded cabochon (likely malachite imitation or dyed agate)

Uncertain; possible malachite (Cu₂CO₃(OH)₂), banded agate (SiO₂), or man-made glass

Tumbled amazonite

Amazonite, green microcline feldspar (KAlSi₃O₈)

Malachite-bearing copper ore, possibly chrysocolla

Malachite (Cu₂CO₃(OH)₂), with possible chrysocolla (Cu₂−xAlx(H₂−xSi₂O₅)(OH)₄·nH₂O) and host rock