Man Made Material, Not A Natural Rock Or Mineral Specimen

Ferruginous Sandstone (with possible Epidote/Chlorite coloring)

Sandstone (SiO2 dominated with Fe2O3 staining)

Botryoidal chalcedony (possibly agate/geode material)

Microcrystalline quartz, SiO₂; commonly chalcedony with quartz-lined cavities and iron-oxide staining

Poppy Jasper

Microcrystalline Quartz (SiO2) with mineral inclusions

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 oxides)

Ferruginous Sandstone (Iron-rich Sandstone)

Ferruginous Arenite

Clear Quartz

SiO2 (Silicon Dioxide)

Polished amethyst pyramid

Amethyst, purple quartz (SiO₂)

Quartz geode

Microcrystalline quartz and drusy quartz (SiO₂), commonly lining a chalcedony-rich cavity

Sandstone

Arenite (SiO2 primarily)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Tumbled milky quartz

Quartz, silicon dioxide (SiO₂)

Shale

Argillite / Shaly Mudstone

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Sandstone (Quartzose)

Sandstone (composed primarily of Quartz: SiO2)

Brown Quartz Pebble

Silicon Dioxide (SiO2)

Dyed Agate Geode Slice

Silicon Dioxide (SiO2)

Tumbled jasper or brecciated jasper

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

Diamond

Carbon (C)

River Cobble (Quartzite or Sandstone)

Clastic sedimentary rock (primarily SiO2)

Blue Dyed Agate Slice

Silicon Dioxide (SiO2) with artificial pigment

Basalt with Quartz/Feldspar Inclusions

Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining

Citrine

Silicon Dioxide (SiO2)

Dyed Agate Slice

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Granite (weathered pebble)

Granite (plutonic igneous rock)

Pink Granite

Phaneritic Plutonic Igneous Rock (high K-feldspar)

Rounded gray stone, likely slate or fine-grained sandstone

Probable slate (low-grade metamorphosed shale) or lithic sandstone; exact identification requires testing

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Sandstone (River Rock)

Arenite (SiO2 based sedimentary rock)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Dyed Agate Slice

Silicon Dioxide (SiO2)

Iron-rich botryoidal limonite/goethite specimen

Limonite (amorphous hydrated iron oxides, chiefly goethite, α-FeO(OH))

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Heat-Treated Citrine

Silicon Dioxide (SiO2) with iron impurities

Moss-covered Rock Fragment

Weathered Rock Fragment with Epilithic Growth

Quartz Crystal Cluster on Matrix

Silicon Dioxide (SiO2)

Chert (Common Variety, Jasper)

Microcrystalline Quartz (SiO2)

Jasper and Basalt Pebble

Polymineralic lithic pebble

Sandstone (Ferruginous)

Arenite (with Iron Oxide cement)

Pink Granite / K-Feldspar

Alkali feldspar granite / Potassium feldspar (Microcline/Orthoclase)

Unakite

Altered Granite (Epidotized Granite)

Quartz (Milky or Druzy Quartz)

Silicon Dioxide (SiO2)