Synthetic Material (Not A Rock Or Mineral)

Sandstone

Sandstone (lithified arenite/wacke)

Limestone

Calcite (CaCO3)

Weathered river stones, likely basaltic andesite and related volcanic rocks

Fine-grained mafic/intermediate volcanic rocks; commonly basalt (plagioclase + pyroxene ± olivine) or andesite (plagioclase + pyroxene ± amphibole)

Ferruginous Quartz Cobble

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Granite Glacial Erratic

Intrusive Phaneritic Felsic Rock (Granite)

Pink granite

Granite; predominantly quartz, K-feldspar, plagioclase, and biotite/hornblende

Granite

Coarse-grained felsic intrusive igneous rock; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende

Quartzite Pebble (with mineral veining)

Metamorphic Quartzite (SiO2)

Obsidian with Slate/Tuff

Volcanic glass (SiO2) with associated pyroclastic rock

Sandstone (specifically Lithic or Quartz Arenite)

Arenite (composed primarily of SiO2)

Pumice or Scoria

Vesicular volcanic rock

Weathered, quartz-rich metamorphic rock (likely schist or gneiss)

Quartz–feldspar–mica schist/gneiss, with surface lichens and iron-oxide staining

River Pebble (Greywacke / Basalt Pebble)

Indeterminate Rounded Pebble (composed of quartz, feldspar, or mafic minerals)

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz geode clusters

Microcrystalline quartz (SiO₂), with possible chalcedony and minor iron-oxide staining

Granitic Quartz with Feldspar

Granite (composed primarily of SiO2 and KAlSi3O8)

Chalcedony

Cryptocrystalline Quartz (SiO2)

River-worn Chert

Microcrystalline Quartz (SiO2)

Fluorite on Host Rock

Calcium Fluoride (CaF2)

Red Sandstone

Ferruginous Sandstone (SiO2 with Fe2O3)

Sandstone (with Iron Oxide)

Arenite with Limonite/Hematite staining

Yellow-brown quartz/chalcedony fragment

Quartz, SiO₂; likely microcrystalline chalcedony with iron-oxide staining

Red Sandstone

Arenite (Fe2O3-rich)

Sandstone

Arenite (SiO2 based)

Obsidian

Obsidian (Volcanic Glass; SiO2 content > 70%)

Dalmatian jasper

Dalmatian stone; commonly a leucocratic alkali-feldspar-rich igneous rock with arfvedsonite or aegirine inclusions

Brecciated jasper/chalcedony (iron-stained silica)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Sandstone (with potential Quartzite characteristics)

Clastic sedimentary rock (primarily SiO2)

Red Sandstone

Sandstone (Iron Oxide Rich)

Biotite (Mica)

Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)

Fossilized Bone / Dinosaur Fossil

Fossilized vertebrate bone (permineralized)

Tumbled agate/chalcedony

Microcrystalline quartz (SiO₂), likely agate or jasper-bearing chalcedony

Red Sandstone

Arenite (Ferruginous Sandstone)

Weathered agate or chalcedony nodule

Microcrystalline quartz (SiO₂), likely agate/chalcedony with iron-oxide staining

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Red Sandstone

Arenite (high iron oxide content)

Cinnabar in Quartz

Silicon Dioxide (Quartz, SiO2) with Mercury Sulfide inclusions (Cinnabar, HgS)

Clear Quartz

Silicon Dioxide (SiO2)

Limestone and Quartz Gravel with Petrified Wood

Sedimentary gravel aggregate and fossilized wood

Sandstone (Ferruginous)

Arenite (with iron oxide cement)

Sandstone (likely Quartzose)

Arenite (primarily SiO2)

Nuummite

Nuummite (Orthorhombic amphiboles: Anthophyllite and Gedrite)