Mineral (Silicate Variety)

Glauconitic Sandstone

Glauconitic Quartz Arenite (with K,Mg,Fe,Al silicate hydroxide)

Glauconitic Sandstone

Glauconitic Quartz Arenite

Likely garnet gemstone

Garnet-group silicate; species cannot be determined from the photo (common red varieties include almandine, Fe₃Al₂(SiO₄)₃, and pyrope, Mg₃Al₂(SiO₄)₃).

Garnet-set butterfly brooch

Likely almandine or pyrope garnet, iron–aluminum silicate (Fe₃Al₂Si₃O₁₂ or Mg₃Al₂Si₃O₁₂)

Amazonite

Potassium Aluminum Silicate (KAlSi3O8)

Red faceted gemstone, possibly garnet

Likely almandine garnet, Fe₃Al₂(SiO₄)₃; identity cannot be confirmed from the image

Polished granite or gneiss cobble

Banding of quartz, feldspar, mica, and ferromagnesian minerals; likely gneiss, possibly weathered granite

Potassium-Rich Silicate Clay (inferred from biological context)

Phyllosilicate group (likely Illite or Smectite within surrounding soil substrate)

Sphalerite with Galena and Calcite / Quartz display specimens

Zinc Iron Sulfide (Zn,Fe)S with Quartz (SiO2) / Aquamarine / Fluorite

Possibly serpentine or weathered greenstone

Serpentinite (magnesium silicate minerals, commonly lizardite/chrysotile); exact identification is uncertain from the image

Tektite

Impactite (Natural Silicate Glass)

Slag (Industrial Glassy Byproduct)

Ferro-silicate Slag

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

Black Tourmaline (Schorl)

Schorl (NaFe2+3Al6(BO3)3Si6O18(OH)4)

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement

Diorite (Dalmatian Stone variant)

Phaneritic Plutonic Igneous Rock (Medium to Fine-grained Diorite)

Quartz-rich rock fragment, possibly granite or quartzite

Indeterminate quartz-bearing silicate rock; likely quartz (SiO₂) with feldspar and/or mica

Sandstone (Glauconitic)

Glauconitic Quartz Sandstone (SiO2 + (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Green Jasper

Silicon Dioxide (SiO2) with mineral inclusions

Quartz pebble

Silicon dioxide (SiO2)

Limonite Sandstone

Ferruginous Sandstone (Hydrated Iron Oxide)

Tumbled serpentine-rich stone

Serpentinite, commonly dominated by antigorite, lizardite, or chrysotile

Leopard skin jasper (orbicular jasper)

Microcrystalline quartz (SiO₂), commonly with iron-oxide and other silicate inclusions

Porphyritic Igneous Rock with Iron Oxide Weathering

Weathered Porphyry (containing Quartz, Feldspar, Amphibole/Biotite, and Hematite/Limonite)

Obsidian

Volcanic glass (SiO2-rich amorphous silicate)

Amazonite

Potassium Aluminum Silicate (KAlSi3O8)

Banded Gneiss (with Quartz Vein)

Gneiss (SiO2 and varied Silicates)

Likely serpentine or weathered greenstone pebble

Serpentine-group minerals, chiefly antigorite/lizardite; possibly chlorite–actinolite greenstone

Quartz Vein in Basalt or Porphyry

Silicate-veined volcanic rock

Amygdaloidal Basalt with Agate/Quartz Infill

Basalt with Secondary Silicate Mineralization (SiO2)

Dalmation Stone

Peralkaline Rock (mixed silicate minerals)

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Jasper

Silicon Dioxide (SiO2) with impurities

Sandstone

Arenite (Clastic Sedimentary Rock)

Moonstone

Potassium Aluminum Silicate (KAlSi3O8)

Peach Moonstone

Potassium Aluminum Silicate (KAlSi3O8)

Green Sandstone

Glauconitic Sandstone

Likely polished black-and-white stone fragment

Indeterminate from image; possibly tourmalinated quartz, black-and-white jasper, or coated stone

Quartz / Common Opal Transition

Silicon Dioxide (SiO2)

Mixed garnet crystal specimens

Garnet-group silicates, likely almandine–spessartine with possible grossular/pyrope varieties; general formula X₃Y₂(SiO₄)₃

Green Jasper

Silicon Dioxide (SiO2) with impurities

Aquamarine

Beryllium aluminum silicate (Be3Al2Si6O18)