Synthetic Or Natural Fiber

Rounded sandstone pebble

Quartz-rich sandstone, likely ferruginous sandstone

River gravel and cobbles

Mixed alluvial clasts, likely including granite, basalt, quartzite, and sandstone

Unakite

Epidotized Granite

Agate (Carnelian / Chalcedony pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz Pebble

Silicon Dioxide (SiO2)

Pumice (Vesicular Lava)

Pumice

Quartz Pebble (Tumbled / River Pebble)

Silicon Dioxide (SiO2)

Green Quartzite / Quartz Pebble

SiO2 (Silicon Dioxide with inclusions)

Sandstone (Quartzose type)

Arenite (primarily SiO2)

Yellow Quartz

SiO2

Emerald

Beryl (variety Emerald), Be3Al2Si6O18 with Cr and/or V

Tumbled granite (likely granitic gneiss)

Granite; primarily quartz (SiO₂), feldspar, and mica, possibly with metamorphic foliation

Weathered brown stone, possibly chert or iron-stained limestone

Uncertain; likely microcrystalline quartz (SiO₂) chert or calcitic limestone (CaCO₃)

Small tumbled brown mineral specimen

Likely quartz variety or iron-stained feldspar; exact identification is uncertain from the image

Likely polished rhyolite or porphyritic volcanic rock

Rhyolite, possibly flow-banded or altered rhyolite; composition mainly quartz and alkali feldspar with minor biotite/iron oxides

Green Quartz (likely Aventurine or Prasiolite)

Silicon Dioxide (SiO2) with inclusions

Quartzite Pebble

Quartzite (SiO2)

Granite Pebble (River Rock)

Granite

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Citrine or Iron-Stained)

Silicon Dioxide (SiO2)

Emerald

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Faceted brown gemstone pendant, likely smoky quartz or champagne topaz

Probably quartz (SiO₂), smoky variety; alternatively topaz (Al₂SiO₄(F,OH)₂)

Yellow Quartz

Silicon Dioxide (SiO2)

Tumbled Yellow Quartz (Golden Quartz / Citrine)

Silicon Dioxide (SiO2)

Yellow Quartz / Citrine Pebble

Silicon Dioxide (SiO2)

Green Chalcedony (Green Agate)

Silicon Dioxide (SiO2)

Tumbled green jasper (possibly serpentine)

Jasper, an opaque microcrystalline variety of quartz (SiO₂); exact identification is uncertain from the image

Polished/tumbled orange calcite-rich stone

Calcite (CaCO₃), possibly with aragonite and iron-oxide inclusions

Porous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

Tumbled green stone, possibly serpentine or aventurine

Serpentine-group minerals (mainly antigorite/lizardite) or quartz-rich green aventurine; image insufficient for certainty

Tumbled pale-green mineral specimen, likely calcite or prehnite

Probably calcite (CaCO₃) or prehnite (Ca₂Al₂Si₃O₁₀(OH)₂); exact identification requires testing

Tumbled carnelian (orange chalcedony)

Carnelian, a microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides

Blue opalite glass cabochon (likely imitation opal)

Man-made opalescent glass; not a natural mineral

Goldstone (brown goldstone)

Man-made aventurine glass, typically copper-bearing silica glass

Yellow Quartz

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine Quartz)

Silicon Dioxide (SiO2)

Polished rhyolite (likely orbicular or flow-banded rhyolite)

Silica-rich volcanic rock, typically quartz–alkali feldspar–plagioclase with volcanic glass and iron oxides

Likely polished serpentine or nephrite jade pebble

Serpentine-group minerals, commonly antigorite/lizardite; possibly nephrite jade (interlocking tremolite-actinolite)

Tumbled banded sandstone pebble

Quartz-rich sandstone (lithified siliciclastic sediment)

Orange Quartz (or Citrine Quartz)

Silicon Dioxide (SiO2)

Citrine or Yellow Quartz

Quartz (SiO2) with iron impurities