Metamorphic Or Sedimentary (With Staining)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz (Ferruginous variety)

Silicon Dioxide (SiO2)

Fossilized bone fragment (probable mammalian tooth or bone)

Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite

Quartz

Silicon Dioxide (SiO2)

Faceted Gemstones (Mixed)

Various (e.g., Corundum, Beryl, Quartz, or synthetic equivalents)

Quartz (partially iron-stained)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2) Pebble

Shungite (or Black Onyx / Obsidian)

Amorphous Carbon (Shungite) / SiO2 (Onyx/Obsidian)

Anthracite Coal

Anthracite (Carbon C)

Iron-Stained Quartzite

Recrystallized Meta-Quartzite (primarily SiO2)

Yellow chalcedony or quartz fragment

Microcrystalline quartz, SiO₂ (tentative; possibly iron-stained chalcedony)

Weathered sandstone or metasedimentary rock

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Red Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartz with Iron Stains

Quartz (SiO2) with iron oxide/hydroxide staining

Weathered quartz-bearing metamorphic rock, likely mica schist or gneiss

Quartz–feldspar–mica assemblage; exact mineral identification requires testing

Tumbled quartz-rich stone, likely milky quartz

Quartz (SiO₂), possibly iron-stained milky quartz or quartzite

Milky Quartz

Silicon Dioxide (SiO2)

Quartzite with Sandstone/Iron staining

Metamorphic Quartzite (SiO2)

Quartz

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Quartz (Iron-stained / Orange Quartz)

Silicon Dioxide (SiO2)

Quartz Boulder

Silicon Dioxide (SiO2)

Likely quartz-rich metamorphic rock (quartzite or quartz-veined schist)

Quartzite/siliceous schist; chiefly quartz (SiO₂), with probable mica and iron-oxide staining

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Granitic Gneiss

Gneiss (quartz-feldspar-mica complex)

Quartz Druzy / Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Hard Sandstone (Quartzite)

Quartz-rich Sedimentary Rock (Proto-Quartzite)

Quartz with inclusions

SiO2

Weathered iron-rich rock, likely shale or slate

Probably ferruginous shale (iron-oxide-stained mudstone); exact identification requires testing

Feldspar (specifically Orthoclase or Plagioclase)

Potassium Aluminum Silicate (KAlSi3O8) or Sodium/Calcium Aluminum Silicate

Calcite (with iron oxide staining)

Calcium Carbonate (CaCO3)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Weathered red-and-green metamorphic rock

Probable epidote-amphibolite or altered schist; exact identification requires testing

Weathered fine-grained stone, likely sandstone or quartzite

Quartz-rich sandstone (possibly weakly metamorphosed quartzite); predominantly SiO₂

Rounded quartz-rich cobble

Likely quartzite or quartz-rich sandstone; exact identification requires a fresh break or hardness test

Rounded quartz-rich pebble (likely vein quartz or quartzite)

Quartz, silicon dioxide (SiO₂); possibly quartzite if metamorphic

Quartz

Silicon Dioxide (SiO2)

Tan quartz-rich rock, likely sandstone or weathered quartzite

Quartz sandstone; primarily SiO₂ with possible feldspar and iron-oxide cement

Quartz

Silicon Dioxide (SiO2)

Likely tumbled quartz or chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony