Sedimentary Rock Or Mineral (Depending On Origin And Purity)

Mixed Mineral and Rock Collection

Mixed geological specimens (Quartz, Amethyst, Rose Quartz, Jasper, Epidote, Chert)

Unidentified brown rock fragment

Indeterminate from image; likely a weathered iron-rich lithic fragment

Sandstone

Sedimentary Rock (Quartz arenite or arkose)

Limestone

Sedimentary Calcite (CaCO3)

Faceted green gemstone, possibly peridot

Uncertain from the image; peridot is gem-quality olivine, (Mg,Fe)₂SiO₄

Sandstone

Sedimentary Rock (Quartz arenite)

Conglomerate

Conglomerate (Sedimentary Rock)

Quartz

Silicon Dioxide (SiO2)

Sandstone

Quartzose Sandstone / Lithic Sandstone

Bauxite

Bauxite (principal ore of aluminum, primarily Al(OH)3)

Chalcedony in Matrix (likely Agatized Coral or Chert)

Silicon Dioxide (SiO2)

Weathered limestone

Calcite-rich carbonate rock (mostly CaCO₃)

Sandstone (Garden Boulder)

Sandstone (SiO2 dominated)

Chert Nodule or Concretion

Microcrystalline Quartz / Sedimentary Nodule

Chert

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Diamond

C (Native Carbon)

Red Aventurine

SiO2 (Silicon Dioxide with Hematite/Goethite inclusions)

Granite

Granite (Plutonic Igneous Rock)

Polished dendritic agate or jasper pebble

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide inclusions

Gold Nugget

Native Gold (Au)

Gold Nugget

Native Gold (Au)

Quartzite (Yellow/Orange variety)

Quartzite (primarily SiO2)

Weathered iron-rich rock fragment

Likely limonite/goethite with hematite and iron-bearing silicates; exact identification requires testing

Weathered quartz-rich pebble

Quartzite or silicified sandstone; predominantly microcrystalline quartz (SiO₂)

Small quartz-rich rock fragment

Likely quartz (SiO₂), possibly a pale granite or feldspar-bearing fragment

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz - SiO2)

Likely small metallic meteorite fragments

Unclassified iron or stony-iron meteorite; mineralogy cannot be confirmed from the image

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Gold Flake / Placer Gold

Native Gold (Au)

Pink-red faceted gemstone, possibly synthetic corundum or spinel

Uncertain; possible ruby (corundum, Al₂O₃) or red spinel (MgAl₂O₄)

Sandstone

Arenite (SiO2 primarily)

Native gold nugget

Native gold (Au), often containing minor silver and copper

Weathered metallic meteorite (probable iron meteorite)

Fe–Ni alloy, mainly kamacite and taenite; exact classification requires chemical and petrographic testing

Tumbled Stone

Silicon dioxide / Various silicates

Opal ring (likely precious opal)

Hydrated amorphous silica, SiO₂·nH₂O; the pictured stone may be natural opal or a lab-created/imitation opal

Fluorite (likely)

Calcium Fluoride (CaF2)

Shale with Pyrite

Clastic sedimentary rock containing Iron Disulfide (FeS2)

Likely blue-gray gneiss

Gneiss, a foliated metamorphic rock; exact mineral composition cannot be confirmed from the image

Basalt with Xenolith

Extrusive Igneous Rock containing Mantle Xenolith

Milky quartz

Quartz (SiO₂)

Chert (Nodule)

Silicon Dioxide (SiO2)

Fossilized Shark Tooth

Chondrichthyes (Class)