Metamorphic Rock

Milky Quartz (Carved Star Beads)

Silicon Dioxide (SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Agate (Polished Nodule)

Agate (Silicon Dioxide, SiO2)

Quartz (Milky Quartz / Quartzite)

Silicon Dioxide (SiO2)

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

White Jade (Nephrite)

Nephrite, Ca2(Mg,Fe)5Si8O22(OH)2

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Green Opal

Hydrated Silica (SiO2·nH2O)

Weathered quartz-rich pebble

Quartz-bearing granitoid or quartzite; exact identification is uncertain from the image

Banded Gneiss

Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)

Banded Rock (likely Quartz-rich)

Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions) - SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2

Green Aventurine

Silicon dioxide (SiO2) with Fuchsite inclusions

Blue quartzite or blue schist (likely quartzite)

Quartz-rich metamorphic rock; predominantly SiO₂, possibly with blue amphibole or dumortierite

Muscovite Mica Schist

Metamorphic rock rich in muscovite mica (KAl2(AlSi3O10)(F,OH)2)

Gold Nugget / Placer Gold

Native Gold (Au)

Tumbled green aventurine quartz

Aventurine quartz, silicon dioxide (SiO₂) with dispersed fuchsite or other mica inclusions

Quartzite pebble

Quartzite (SiO2)

Lapis Lazuli

Lapis Lazuli (Complex aggregate including Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Unakite

Altered Granite (Epidote, Orthoclase Feldspar, Quartz)

Amethyst and Ruby in Zoisite

Silicon Dioxide (SiO2) and Anyolite (Zoisite-Hornblende-Ruby mix)

Unidentified gray stone

Likely quartz-rich stone; exact identification is not possible from the image

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Green Aventurine

Aventurine Quartz (SiO2 with inclusions)

Likely iron-rich meteorite or weathered sulfide-bearing rock

Unconfirmed; possible ordinary chondrite (stony meteorite) or iron-oxide/sulfide-bearing terrestrial rock

Rounded quartz-rich pebble

Likely granitoid-derived quartz–feldspar cobble; exact identification requires testing

Small brown mineral fragment, possibly quartz/chert

Uncertain; likely microcrystalline quartz (SiO₂) or a weathered silicate rock

Weathered green-gray stone, likely serpentinite or chlorite-rich metamorphic rock

Probable serpentinite (antigorite–lizardite), possibly chlorite schist or altered basalt

Epidote with Quartz/Feldspar

Epidote (Ca2(Al, Fe)3(SiO4)3(OH)) with associated minerals in a host rock

Quartz with Schist Inclusion

Crystalline Silicon Dioxide (SiO2) with Muscovite/Biotite Schist

Quartzite

Quartzite (SiO2)

Biotite Schist

Biotite Schist (Metamorphic Rock featuring K(Mg,Fe)3AlSi3O10(OH)2)

Small polished or naturally worn stone, possibly quartz-bearing rock

Indeterminate from the blurred image; likely quartz (SiO₂) or a pale feldspar-rich fragment

Rounded gray-green pebble, likely basalt or fine-grained metamorphic rock

Probable basalt (plagioclase–pyroxene–iron oxide aggregate); exact identification requires testing

Green Aventurine

Silicon Dioxide with Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Quartz with Schist Inclusion

Quartz (SiO2) with micaceous schist inclusions

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite

Quartz-rich rock fragment, possibly granite or quartzite

Primarily quartz (SiO₂), with possible feldspar and iron-oxide staining

Common Quartz Pebble

Silicon dioxide (SiO2) rock fragment

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2

Green Aventurine

Aventurine Quartz (SiO2 with inclusions of Fuchsite)