Unknown (Likely Sedimentary Or Metamorphic)

Quartz

Silicon Dioxide (SiO2)

Banded metamorphic rock, likely gneiss or migmatitic gneiss

Quartz–feldspar–mica gneiss; exact identification requires a fresh surface and mineral tests

Banded gneiss (weathered glacial erratic)

Gneiss; typically quartz–feldspar–biotite ± hornblende

Feldspar-rich Quartzite

Meta-arkose (Quartz-Feldspar Quartzite)

Garnet-bearing schist or gneiss

Garnet-mica schist/gneiss; chiefly quartz, feldspar, mica, and almandine–pyrope garnet

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Likely weathered metamorphic rock (possibly schist or gneiss)

Indeterminate; probable mica-rich quartz–feldspar metamorphic rock

Weathered metamorphic rock, likely schist or gneiss

Quartz–feldspar–mica metamorphic rock; exact identification requires testing

Rounded granitic gneiss cobble

Foliated quartz–feldspar–mica gneiss; likely granitoid-derived

Raw garnet-rich metamorphic rock

Likely garnet-bearing schist or garnetite; garnet-group silicates, commonly almandine (Fe₃Al₂Si₃O₁₂)

Likely weathered gneiss

Foliated metamorphic rock, commonly quartz–feldspar–mica gneiss

Likely gneissic amphibolite or banded metamorphic rock

Hornblende–biotite gneiss/amphibolite; exact identification requires a fresh surface or thin section

Weathered quartz-bearing metamorphic rock, likely mica schist or gneiss

Quartz–feldspar–mica assemblage; exact mineral identification requires testing

Gray slate or fine-grained metamorphic rock

Slate–phyllite spectrum; predominantly fine-grained quartz, mica, and chlorite

Raw selenite (gypsum)

Gypsum, CaSO₄·2H₂O; translucent variety selenite

Garnet (likely Almandine)

Almandine Garnet, Fe3Al2(SiO4)3

Sandstone (with potentially metamorphic or basaltic bands)

Arenite / Lithic Wacke

Weathered quartz-rich metamorphic rock

Likely quartzite or quartz-veined schist; primarily SiO₂ with possible mica, feldspar, and iron oxides

K2 Stone

Azurite in Granite

Unidentified gray metamorphic rock, likely schist or gneiss

Quartz–feldspar–mica metamorphic rock; exact identification requires testing

Quartzite pebble with Mafic inclusions

Quartzite (SiO2)

Weathered sandstone or iron-stained quartzite

Quartz-rich sandstone (SiO₂-dominated), possibly metamorphosed to quartzite

Weathered gray-green rock fragment

Likely shale or mudstone; exact identification requires testing

Banded metamorphic rock, likely banded gneiss

Gneiss, probably biotite–quartz–feldspar gneiss

Slate

Slate; predominantly fine-grained phyllosilicates (muscovite/illite, chlorite) with quartz and feldspar

Banded metamorphic rock, likely mica schist

Mica schist, chiefly quartz, muscovite/biotite, and feldspar

Weathered gray metamorphic rock, likely slate or phyllite

Fine-grained foliated metamorphic rock; commonly quartz–mica–chlorite, possibly chlorite phyllite

Weathered, iron-stained rock (likely sandstone or breccia)

Indeterminate clastic sedimentary rock; possible ferruginous sandstone or weathered breccia

Weathered, quartz-rich metamorphic rock (likely schist or gneiss)

Quartz–feldspar–mica schist/gneiss, with surface lichens and iron-oxide staining

Weathered foliated metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface and mineral tests

Quartz (Milk/Citrine variety)

Silicon Dioxide (SiO2)

Weathered metamorphic rock, likely schist or slate

Foliated pelitic metamorphic rock; commonly muscovite–chlorite schist or phyllite

Quartzite River Stone

Metamorphosed Quartz-rich Sandstone (SiO2)

Likely pyrite-bearing metamorphic rock

Quartz–mica schist or phyllite with disseminated pyrite (FeS₂)

Mixed polished river stones

Likely quartz, quartzite, chert/jasper, and possibly limestone or marble

Felsic gneiss, likely granitic gneiss

Quartz–feldspar–mica gneiss; commonly quartz + plagioclase/K-feldspar + biotite or hornblende

Agate

Chalcedony (SiO2) with impurities

Weathered quartz-rich rock, possibly quartzite or sandstone

Likely quartzite (mostly SiO₂), though heavily weathered sandstone is possible

Gneiss with Quartz Veining

Gneiss (High-grade Regional Metamorphic Rock)

Quartz-rich sandstone or quartzite

Quartz (SiO₂)-rich clastic rock; possibly weakly metamorphosed quartzite

Quartz-rich weathered rock, possibly quartzite

Quartzite (mostly SiO₂); exact identification is uncertain from the image

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)