Mineral, Possibly Rock Fragment Containing A Mineral

Weathered granitic rock fragment

Likely granite or granodiorite, composed mainly of quartz, feldspar, and mica

Likely polished dark stone or glassy mineral bead

Indeterminate; possibly obsidian, hematite, or a dark agate

Conglomerate

Conglomerate (Clastic sedimentary rock)

Fossil bivalve shell

Fossilized or partially mineralized bivalve; exact genus cannot be determined from the image

Brecciated jasper/chalcedony

Silica-rich breccia composed mainly of microcrystalline quartz (SiO₂), with iron-oxide and possibly epidote or chlorite inclusions

Weathered granite-like rock

Granite, likely biotite-bearing; exact identification is uncertain from the image

Jasper and Epidote in Quartzite

Metamorphic rock containing microcrystalline quartz, epidote, and jasper

Yellow Quartz (possibly dyed)

Silicon Dioxide (SiO2)

Possible weathered mica-rich metamorphic fragment

Mica schist or phyllite (quartz–mica assemblage; identification uncertain from image)

Shale

Shale (clay-rich mudstone)

Blue copper-mineral rock, likely chrysocolla-bearing copper ore

Chrysocolla (hydrated copper aluminosilicate), possibly with malachite, quartz, or host rock

Tree Agate

Dendritic Agate (Silicon Dioxide, SiO2)

Limestone (fossiliferous)

Calcium Carbonate (CaCO3)

Tumbled epidote-bearing granite or amphibolite

Quartz–feldspar rock with dark amphibole/biotite and epidote; exact identification is uncertain from the image

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Tumbled yellow jasper or petrified wood fragment

Microcrystalline quartz (chalcedony), SiO₂, possibly iron-oxide-bearing jasper

River Pebble

Lithified rock fragment (variable composition)

Pale green tumbled mineral fragment, likely serpentine or green calcite

Probable serpentine-group mineral (Mg3Si2O5(OH)4) or, less likely, calcite (CaCO3); identification is uncertain from the photograph

Sandstone

Clastic sedimentary rock (Quartz arenite)

Dark vesicular volcanic rock, likely basaltic scoria

Scoria (vesicular basalt; composition commonly plagioclase, pyroxene, and iron-rich glass)

Concrete Fragment

Hardened Portland Cement Composite

Vesicular basalt (possibly amygdaloidal basalt)

Basalt, chiefly plagioclase feldspar and pyroxene, with possible olivine and secondary mineral infillings

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Malachite

Malachite — Cu₂CO₃(OH)₂, hydrated copper carbonate

Snowflake Obsidian

Volcanic glass containing Cristobalite (SiO2)

Sandstone

Sedimentary Rock (Quartz Sandstone)

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium), CuAl6(PO4)4(OH)8·4H2O

Mica Schist

Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)

Sandstone (Iron-stained)

Arenite with Limonite/Hematite staining

Sandstone

Clastic sedimentary rock (primarily SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Granite

Granite

Sandstone (with Iron Staining)

Arenite (primarily SiO2 with Fe2O3/FeO(OH) oxides)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Clastic Sedimentary Rock

Fossiliferous Limestone (or Bryozoan/Coral Fossil Pebble)

Biogenic Sedimentary Rock (Calcium Carbonate, CaCO3)

Light-colored quartz-rich stone, possibly milky quartz

Quartz (SiO₂), provisional identification

Banded Agate (Geode Fragment)

Silicon Dioxide (SiO2) - Variety Agate

White limestone or chalky carbonate rock

Calcite-rich limestone; possibly chalk (CaCO₃)

Granite with Mafic Xenolith

Intrusive Igneous Rock (Felsic to Intermediate)

Quartz Geode Fragment

Silicon Dioxide (SiO2)