Uncertain

Small water-worn pebble, likely granite or granitic rock

Granite (tentative; exact identification is uncertain from the photo)

Likely gneiss

Quartz–feldspar–mica gneiss (visual identification is uncertain)

Tumbled milky chalcedony (likely common opal or quartz-rich chalcedony)

Chalcedony, microcrystalline SiO₂; identification is uncertain from the photo

Faceted black gemstone, likely black spinel

Spinel (MgAl₂O₄); identification from the image is uncertain

Possible weathered quartz or quartz-rich pebble

Quartz (SiO₂), identification uncertain from the blurred image

Rough quartz crystal, possibly milky quartz

Quartz, SiO₂; exact variety uncertain from the image

Likely rough sapphire (corundum)

Corundum, Al₂O₃; identification is uncertain from the photo

Dark mafic rock, possibly basalt

Likely basalt; precise identification is uncertain from the image

Likely quartz-rich metamorphic pebble

Possibly quartzite; exact identification is uncertain from the photo

Tumbled white stone, possibly milky quartz

Likely quartz (SiO₂); identification is uncertain from the photo

Rounded light-colored pebble, likely quartzite

Quartzite (probable; exact identification is uncertain from the image)

Faceted black gemstone, likely black spinel

Spinel, MgAl₂O₄ (identification from appearance is uncertain)

Brown-orange quartz pebble, possibly iron-stained quartzite

Quartz (SiO₂); exact identification is uncertain from the photograph

Rounded agate or chalcedony pebble

Microcrystalline quartz, SiO₂; identification is uncertain from the photo

Colorless faceted gemstone, likely a diamond in a ring setting

Diamond (carbon, C); identification from the image is uncertain

Small water-worn pebble, likely quartz-rich

Rock fragment of uncertain composition; possibly quartzite or chert

Faceted yellow gemstone, likely citrine

Quartz (SiO₂); identification is uncertain from the image alone

Pink faceted gemstone, possibly pink sapphire

Uncertain from the image; possibly corundum (Al₂O₃)

Polished banded calcite (possibly onyx marble)

Calcite, CaCO₃; exact variety is uncertain from the image

Blue glassy gemstone cabochon, likely dyed chalcedony or glass

Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)

Tumbled pink granite

Granite (quartz, feldspar, and mica; exact variety uncertain)

Polished brown pebble, possibly agate or jasper

Uncertain; likely microcrystalline quartz (SiO₂) if agate/jasper

Small dark rock fragment (likely basalt or slag)

Tentatively basalt; exact identification is uncertain from the photograph

Yellow faceted gemstone, likely citrine or yellow sapphire

Uncertain; probable quartz (SiO₂) or corundum (Al₂O₃)

Dark fine-grained rock fragment

Probably basalt or basaltic scoria; visual identification is uncertain

Small reddish-brown mineral fragment

Uncertain; possibly iron-stained quartz, feldspar, or garnet

Blue-dyed tumbled stone, likely calcite or quartz

Uncertain; commonly dyed quartz (SiO₂) or calcite (CaCO₃)

Likely garnet-bearing metamorphic fragment

Uncertain; possibly almandine garnet in mica schist or amphibolite

Tumbled dark metallic mineral specimen

Likely hematite or magnetite; identification is uncertain from the photograph

Tumbled milky quartz (probable quartzite or chalcedony pebble)

Quartz, SiO₂; exact variety uncertain from the image

Blue-green stone, likely copper-mineral-bearing rock

Uncertain; possibly chrysocolla- or copper-carbonate-bearing material

Rounded gray pebble

Uncertain; likely quartz-rich sandstone, quartzite, or graywacke

Likely iron-rich rock or weathered metallic mineral fragment

Uncertain; possibly limonite/goethite or iron-bearing slag

Likely fluorescent mineral specimen

Uncertain; possibly willemite (Zn₂SiO₄) or fluorite (CaF₂)

Weathered brown rock, likely sandstone

Quartz-rich sandstone (composition uncertain from image)

Polished mixed rock, likely orbicular/epidote-bearing granite or basalt

Uncertain; probable quartz–feldspar–amphibole/epidote aggregate

Weathered rock fragment (likely granite or quartz-rich sandstone)

Uncertain; possible granitic fragment containing quartz and feldspar

Possible tektite or dark volcanic rock fragment

Uncertain; likely natural silicate glass (tektite) or basalt

Tumbled tan pebble, likely sandstone or chert

Uncertain; probable quartz-rich sandstone (SiO₂-bearing)

Likely weathered gray stone or chert fragment

Uncertain; possibly microcrystalline quartz (SiO₂)-rich chert

Weathered sandstone or quartzite cobble

Quartz-rich sandstone; possibly weakly metamorphosed quartzite (SiO₂-dominant)

White quartz in dark matrix (likely quartz-bearing breccia or polished composite specimen)

Quartz, SiO₂, in an unidentified dark silicate matrix