Industrial Byproduct (Anthropogenic Rock Like Material)

Tumbled amber-colored chalcedony or jasper

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

Quartz Pebble

Silicon Dioxide (SiO2)

Silver (Sterling Silver Jewelry)

Argentum (Ag) mixed with Copper (Cu)

Amethyst cluster (quartz geode fragment)

Amethyst, purple variety of quartz; silicon dioxide (SiO₂) colored mainly by iron-related defects

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Weathered quartz-bearing rock, possibly calcite vein fragment

Indeterminate; likely quartz (SiO₂) with carbonate minerals such as calcite (CaCO₃)

Sandstone

Arenite (SiO2 primarily)

Small dark metallic-looking rock fragment

Undetermined; possibly iron oxide-rich material or a metallic mineral

Quartz Sand Gravel

Silicon Dioxide (SiO2)

Fossilized wood, likely silicified petrified wood

Silicified wood (fossil wood; commonly quartz/chalcedony replacing organic tissue)

Diamond (or Simulant)

Carbon (C) or relevant simulant formula (e.g., ZrO2 for Cubic Zirconia)

Quartzite

SiO2 (Silicon Dioxide)

Faceted glass-like gemstone object

Likely synthetic glass or cubic zirconia; exact material cannot be confirmed from the image

Weathered jasper-rich breccia

Silicified iron-rich breccia; primarily microcrystalline quartz (SiO₂) with iron oxides/hydroxides

Tumbled quartz-rich pebble

Likely milky quartz with a dark mafic inclusion or attached basalt; exact identification requires testing

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Tumbled, iron-stained quartz-rich pebble

Likely quartz/chalcedony with iron-oxide staining; exact rock type cannot be determined from the image

Limestone

CaCO3 (principally Calcite)

Rounded pebble, likely quartz-rich

Undetermined quartz-rich lithic pebble; exact rock type cannot be identified from the photograph

Plume Agate or Moss Agate

Agate (SiO2)

Tumbled rose quartz (probable)

Quartz, silicon dioxide (SiO₂), rose-colored variety

Pegmatite or Graphic Granite

Intrusive Igneous Rock

Pegmatite

Pegmatite (felsic intrusive igneous rock)

Limestone

Calcium Carbonate (CaCO3)

Likely coral fragment or calcareous fossil

Aragonite/calcite (CaCO₃), possibly fossil coral such as Pocillopora or a bryozoan

Granitic Pegmatite

Pegmatitic Granite

Quartzite

Quartzite (primarily SiO2)

Tumbled picture jasper

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

Uncertain small stone; possibly weathered quartz-bearing rock

Indeterminate from image; candidate materials include quartz-rich pebble or altered silicate rock

Unidentified weathered mineral/rock fragment

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

Greenish altered rock, possibly serpentinite or chlorite-rich schist

Tentative: serpentine-group minerals, chiefly antigorite/lizardite, or chlorite–actinolite assemblage

Petrified Wood

Fossilized wood / Silicified wood

Basalt Pebble

Basalt (Mafic volcanic rock)

Polished Picasso jasper

Silicified carbonate rock, commonly marketed as Picasso jasper; composition varies and is not a single mineral species

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz/chalcedony with iron- and manganese-bearing inclusions; SiO₂

Concrete Paver (Artificial Cementitious Rock)

Hydrated Portland Cement Aggregate

Coquina (Fossiliferous Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chalcopyrite

Chalcopyrite (CuFeS2)

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing granitoid or quartzite

Iron-rich breccia or hematite-bearing jasper

Hematite–quartz jasper (silica-rich ironstone), possibly brecciated

N/A - Man-made object (Jewelry Chain)

Antiqued or Oxidized Metal Chain (often Steel or Brass)

Basalt (Weathered)

Extrusive Igneous Rock (Mafic composition)