Mineralogical Specimen

Quartz (Iron-stained or Rose variant)

Silicon Dioxide (SiO2)

Quartzite Pebble

Quartzite (primarily SiO2)

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Small weathered rock fragment, possibly quartz-rich

Unidentified lithic fragment; species cannot be determined from the image

Fossil shark tooth

Likely fossilized shark tooth, possibly Carcharhinus or Otodus species

Weathered brown rock, possibly iron-rich sandstone or limonite

Tentative: ferruginous sandstone (quartz with iron oxides) or limonite/goethite-rich material

Diamond

Carbon (C)

Gold-bearing Quartz / Auriferous River Rock

Lode Gold in Quartz Matrix (SiO2 + Au)

Basalt with Quartz/Calcite Inclusion

Aphanitic Mafic Igneous Rock (Basalt) with SiO2 or CaCO3 vein

Kidney Stone (Medical Specimen)

Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O

Amethyst

Silicon dioxide (SiO2) with iron impurities

Copper Ore / Altered Granodiorite

Cupriferous rock with silicate gangue

Yellow Quartzite River Stone

Quartzite (SiO2)

Bull Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂ with minor iron-oxide staining and possible feldspar/mica

Iron-oxide-stained sandstone

Quartz-rich sandstone, likely cemented by iron oxides (hematite/goethite)

Pink Granite

Phaneritic Felsic Igneous Rock

Iron-stained quartz crystal aggregate

Quartz (SiO₂), likely included or coated with limonite/goethite

Fossiliferous limestone, possibly coral limestone

Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃), with probable fossil coral or shell structures

Tumbled citrine (likely heat-treated amethyst or quartz)

Quartz, SiO₂; yellow coloration from iron impurities or irradiation/heat treatment

Rose Quartz in Matrix

Silicon Dioxide (SiO2) with traces of Titanium, Iron, or Manganese

Dumortierite Quartz

Dumortierite-bearing Quartz (SiO2 with Al7BO3(SiO4)3O3)

Sandstone (Ferruginous)

Sandstone (clastic sedimentary rock, mainly SiO2 with iron oxide cement)

Clear Quartz

Silicon dioxide (SiO2)

Orange Calcite (Iron-Stained)

Calcium Carbonate (CaCO3)

Chert (Smooth River Pebble)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Cryptocrystalline Quartz (SiO2)

River Pebble (Gneiss or Quartzite variant)

Metamorphic rock specimen (likely Quartzite or Gneiss)

Iron-stained quartzite

Quartzite, composed predominantly of recrystallized quartz (SiO₂), with iron-oxide staining

Jasper

Microcrystalline Quartz (SiO2)

Chert / Jasper

Silicon Dioxide (SiO2)

Limonite (Ironstone) Concretion

FeO(OH)·nH2O (Hydrous ferric oxide)

Shark Tooth Fossil

Carcharodonta (order Lamniformes), likely Carcharias spp.

Weathered iron-rich chert or ferruginous quartzite

Microcrystalline quartz (SiO₂), stained/coated by iron oxides such as goethite and hematite

Pegmatitic quartz–feldspar–mica rock

Granitic pegmatite, composed mainly of quartz (SiO₂), feldspar, and black mica (biotite); possible accessory tourmaline or schorl

White Precious Opal

Hydrated Silica (SiO2·nH2O)

Chert (Chert breccia)

SiO2 (Silicon Dioxide)

Quartz pebble with host matrix

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Basalt (River Stone)

Basalt (SiO2 range 45-52%)

Quartz / Quartzite

Silicon Dioxide (SiO2)