Mineral Like (Natural Glass)

Star Ruby

Corundum (Al2O3 with chromium and rutile inclusions)

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

Goldstone

Aventurine glass (Synthetic glass with copper inclusions)

Obsidian

Volcanic glass (SiO2 + impurities)

Polished brecciated jasper

Jasper, opaque microcrystalline quartz (SiO₂), likely brecciated jasper with iron-oxide and dark silicate inclusions

Diamond

Carbon (C)

Polished Tumbled Fluorite (or Dark Amethyst)

CaF2 (Calcium Fluoride) / SiO2 (Silicon Dioxide)

Hag Stone

Perforated Chert (Microcrystalline Silica, SiO2)

Jasper River Stone

Silicon Dioxide (SiO2) with iron oxide inclusions

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (SiO2 dominated)

Goldstone (Synthetic Aventurescence Glass)

Cuprous Aventurescent Glass (Silicon Dioxide with Copper inclusions)

Lapis Lazuli

Lapis Lazuli (aggregate of Lazurite, Calcite, and Pyrite)

Muscovite Mica Schist

Muscovite Schist (KAl2(AlSi3O10)(OH)2)

Diamond

Carbon (C)

River Agate (Chert/Chalcedony)

Cryptocrystalline Quartz (SiO2)

Obsidian

Volcanic Glass (SiO2 + minor impurities)

Shale (or Slate / Coal / Jet)

Laminated fine-grained sedimentary rock (predominantly clay minerals)

Polished tiger’s-eye

Chatoyant quartz, mainly fibrous crocidolite pseudomorphed by quartz (SiO₂)

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky quartz

Quartz (SiO₂), brown-to-gray smoky variety

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, FeO(OH)·nH2O)

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

Travertine (Tufa)

Terrestrial Sedimentary Limestone (CaCO3)

Fossil gastropod shell

Fossilized marine gastropod; exact genus/species requires locality and examination

Limonite (Yellow Ochre)

FeO(OH)·nH2O (Hydrous iron(III) oxide-hydroxide mixture)

Tumbled purple agate (likely grape agate or amethystine chalcedony)

Microcrystalline quartz, SiO₂; purple coloration commonly from iron, manganese, or inclusions

Yellow calcite crystal cluster with calcite fragment

Calcite, calcium carbonate (CaCO₃)

Tumbled brown stone, likely tiger’s-eye or jasper

Quartz-rich microcrystalline silica, likely SiO₂ (possible tiger’s-eye; identification uncertain from image)

Chert

Microcrystalline quartz (SiO2)

Yellow Quartz (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Shale

Shale (clay-sized silicate minerals)

Sandstone (Yellow/Tan)

Clastic sedimentary rock (primarily SiO2 with iron oxide staining)

Snowflake Obsidian

Hydrated Volcanic Glass with Cristobalite inclusions

Glauconite (Green Sandstone)

Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2

Shale (or Mudstone)

Siltstone/Argillite (composed mainly of clay and silt-sized particles)

Shale

Lutaceous sedimentary rock

Sandstone (Cross-bedded Drill Core)

Clastic Sedimentary Rock (primarily SiO2)

Muscovite

Muscovite, KAl2(AlSi3O10)(OH)2