Mineral Specimen

River Cobble (Sandstone)

Arenite (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron-oxide inclusions (SiO2 primarily)

Sandstone (Greywacke)

Arenite/Greywacke (SiO2 major)

Sandstone Pebble

Arenite (primarily Quartz, SiO2)

Sandstone (Quartzite-rich Pebble)

Arenite (primarily SiO2)

Sandstone

Arenite (primarily SiO2)

Polished Septarian Nodule

Septarian calcite–aragonite concretion, commonly with barite or celestine

Quartz Pebble

Silicon Dioxide (SiO2)

Vein-filled Basalt or Diabase Pebble

Mafic igneous rock with quartz/calcite veins

Dragon Blood Jasper

Epidote with Pietersite or Red Jasper (Silicate mineral)

Citrine Geode

Citrine (Silicon Dioxide, SiO2)

Green Calcite

Calcium Carbonate (CaCO3) with trace impurities

Dendritic Agate (specifically Orange/Tumbled)

Silicon Dioxide (SiO2) with Oxide Inclusions

Quartz Pebble

Silicon Dioxide (SiO2)

Likely weathered quartz-bearing rock fragment

Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite

Quartz Pebble

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chrysocolla

Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Greenstone

Greenschist (composed of chlorite, actinolite, and epidote)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Howlite

Howlite, Ca₂B₅SiO₉(OH)₅

Milky quartz

Quartz (silicon dioxide, SiO₂)

Tumbled brown stone, likely smoky quartz or brown jasper

Probable smoky quartz (SiO₂) or iron-rich jasper (microcrystalline SiO₂); image alone is insufficient for certainty

Polished amethyst pyramid

Amethyst, purple quartz (SiO₂)

Sapphire

Corundum (Al2O3)

Quartz (Raw Chunk)

Silicon Dioxide (SiO2)

Agate (Common Chalcedony)

Silicon Dioxide (SiO2)

Diamond (as featured in jewelry)

Diamond (C - pure carbon)

Dyed Blue Agate

Silicon Dioxide (SiO2)

Quartz

Silicon dioxide (SiO2)

Ocean Jasper

Orbicular Jasper / Silicate

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with iron-oxide and feldspar inclusions; commonly marketed as Ocean Jasper

Orange-yellow calcite crystal

Calcite (CaCO₃), likely honey/orange calcite

Amethyst cluster

Quartz, SiO₂, violet variety (amethyst)

Carnelian

Carnelian (SiO2 with iron oxide impurities)

Diamond

Diamond (pure carbon, C)

Agate

SiO2

Yellow Quartz (Citrinated Quartz)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide)

Milky quartz (quartz crystal)

Quartz, silicon dioxide (SiO₂)

Tumbled brown agate

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions