Not A Rock Or Mineral (Anthropogenic Material)

Weathered granite or granitic gneiss fragment

Granite; predominantly quartz, feldspar, and mica (exact identification requires testing)

Sandstone

Arenite (SiO2 based)

Quartz (Milky/Crystalline)

Silicon Dioxide (SiO2)

Porphyritic Basalt or Porphyritic Andesite

Porphyritic volcanic rock

Sandstone (Banded)

Clastic sedimentary rock (primarily SiO2)

Tumbled greenstone, likely serpentine or altered basalt

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; possibly chlorite/epidote-bearing mafic rock

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Granite

Granite

Sandstone

Arenite (Siliclastic sedimentary rock)

Weathered granite fragment

Granite, primarily quartz, feldspar, and mica

Dalmatian jasper (polished stone beads)

Commercial “Dalmatian jasper”; typically a feldspar-rich rock with dark aegirine or arfvedsonite inclusions, not true jasper

Turquoise ring (likely stabilized or imitation turquoise)

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact material is uncertain from the image

Sandstone (Ferruginous)

Arenite (Siliclastic Sedimentary Rock)

Sandstone

Sandstone (SiO2-dominated clastic rock)

Coarse-grained granite or granitic pegmatite fragment

Granite; primarily quartz, feldspar, and mica

Serpentinite (often called Jade or Nephrite substitute)

Serpentinite (composed primarily of Antigorite, Lizardite, or Chrysotile)

Sandstone

Sandstone (SiO2 with iron oxides and clay)

Ferro-Manganese Slag

Vitreous Silicate Slag

Sandstone

Sandstone (SiO2 rich)

Boulder Opal

Hydrated Silica (SiO2·nH2O)

Tumbled amber-colored agate or chalcedony

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/agate

Sandstone

Quartzose Sandstone (Sedimentary Rock)

Sandstone

Arenite (SiO2 primarily)

Red jasper

Jasper, an opaque microcrystalline quartz variety (SiO₂), colored mainly by iron oxides

Sandstone

Sedimentary Rock (Quartz arenite)

Unidentified weathered mineral/rock fragment

Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen

Granite fragment

Granite; mainly quartz (SiO₂), feldspar, and mica

Green glassy slag (often sold as “sea glass” or “green obsidian”)

Industrial vitreous slag; primarily amorphous silicate glass, composition variable

Poppy Jasper

Microcrystalline Quartz (SiO2) with mineral inclusions

Sandstone

Arenite (predominantly SiO2)

Sandstone

Arenite (SiO2 predominantly)

Sandstone

Arenite (primarily Quartz and Feldspar)

Gneiss

Foliated Metamorphic Rock (Gneiss)

Shale

Shale (clastic sedimentary rock)

Red Sandstone

Sandstone (Quartz Arenite / Arkose with Hematite cement)

Sandstone

Arenite (SiO2 primarily)

Milky quartz with dark mineral veins

Quartz, silicon dioxide (SiO₂), likely massive vein quartz; dark veins may be chlorite, mica, iron/manganese oxides, or a sulfide mineral

Fossil bivalve or brachiopod in sedimentary rock

Unidentified fossil shell impression; likely a ribbed bivalve or brachiopod preserved in shale/siltstone

Sandstone Pebble

Arenite (SiO2 based)

Ocean Jasper or Orbicular Jasper

SiO2

Brecciated quartz vein rock

Quartz (SiO₂), with iron-oxide staining and likely feldspar/carbonate gangue

Tumbled blue-gray stone, likely basalt or slate

Probable fine-grained basalt; exact identification is uncertain from the photograph