Mineraloid (Human Made Geological Specimen)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartz (Clear Quartz and Rose Quartz variants)

Silicon Dioxide (SiO2)

Amethyst

Quartz (SiO2) variety

Sandstone (Ferruginous)

Arenite (Fe2O3 stained)

Turritella (Gastropod Fossil)

Turritella (Genus of gastropods), CaCO3 (Calcium Carbonate or Silicified Agate)

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Granite (Fine-grained)

Phaneritic Felsic Igneous Rock

Porphyritic Basalt

Porphyritic Basalt (containing Plagioclase or Alkali Feldspar phenocrysts)

Dyed Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Sandstone (Ferruginous Concretion)

Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement

Calamites (Fossilized Horsetail)

Calamites suckowii (Family: Calamitaceae)

Granite

Granite (composed primarily of Quartz SiO2, Feldspar (KAlSi3O8), and Mica)

Sandstone Concretion

Arenaceous concretion (primarily SiO2 with Fe2O3 staining)

Fossil Coral (Rugosa or Solitary Coral)

Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)

Fossilized Bone Fragment

Permineralized Skeletal Element (Likely Vertebrate)

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

Dinosaur Bone (Gembone)

Petrified Dinosaur Bone (Apatite/Silica replacement)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Fossiliferous Limestone with Brachiopod Mold

Calcium Carbonate (CaCO3) matrix containing Brachiopoda fossil impressions

Amygdaloidal Basalt

Amygdaloidal Basalt containing Zeolite or Quartz (SiO2/Silicates)

Epidote (or Epidote-rich rock)

Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Garnet Schist

Garnetiferous Mica Schist

Ironstone Concretion (Limonite/Goethite)

Ferruginous Sandstone / Ironstone (FeO(OH)·nH2O)

Quartz Geode (Cracked)

Quartz (Silicon Dioxide, SiO2)

Gold Nugget

Native Gold (Au)

Geode (unopened)

Silica-filled Concretion (SiO2)

Septarian Nodule (Septaria)

Septarian Nodule (Calcium Carbonate/Aragonite/Calcite Concretion)

Sandstone Concretion

Moqui Marble (Iron-oxide concretion)

Porphyritic Basalt

Basalt with plagioclase phenocrysts

Honeycomb Coral Fossil

Favosites (extinct genus of tabulate coral)

Muscovite Mica (with Quartz matrix)

Muscovite - KAl2(AlSi3O10)(OH)2

Mixed Mineral Specimens

Mixed Silicates, Oxides, and Phosphates (SiO₂, Ca₅(PO₄)₃(F,Cl,OH), Na₈Al₆Si₆O₂₄Cl₂, etc.)

Granite

Phaneritic Felsic Igneous Rock

Sandstone

Arenite (SiO2 based with various mineral cements)

White Quartz Pebble (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz / Quartzite

Silicon Dioxide (SiO2)

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)