Mineral, Possibly Rock Fragment Containing A Mineral

Greenish translucent mineral fragment

Indeterminate; possibly serpentine, epidote, or green glassy feldspar

Small seashell fossil or shell fragment

Likely calcium-carbonate shell material, chiefly aragonite or calcite; exact species indeterminate

Likely weathered quartz-bearing rock fragment

Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite

Concretion

Septarian concretion (likely containing Calcite or Siderite)

Weathered basalt or iron-rich river cobble

Basalt, likely with iron-oxide staining; exact identification requires testing

Iron-rich sandstone or laterite fragment

Ferruginous sandstone; possibly laterite/goethite-rich ironstone

Kimberlite

Ultramafic igneous rock

Sedimentary Rock Fragments

Clastic Sedimentary Rock

Brecciated jasper, possibly rainforest jasper or brecciated rhyolite

Brecciated microcrystalline quartz (SiO₂), commonly called jasper; the green portions may contain epidote, chlorite, or iron-bearing silicates, while red-brown areas are typically hematite or other iron oxides

Weathered iron-rich rock fragment

Uncertain; possibly limonite/goethite-bearing ironstone or weathered basalt

Small quartz-rich rock fragment (tentative)

Quartz, silicon dioxide (SiO₂), possibly in a feldspar-bearing granite fragment

Weathered quartz-rich stone, possibly chalcedony or calcite

Likely microcrystalline quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Quartz-rich rock fragment, likely milky quartz

Quartz (silicon dioxide, SiO₂), possibly an iron-stained quartz vein fragment

Asphalt (Bituminous Concrete)

Composite material (bitumen binder with mineral aggregate)

Weathered brown stone, possibly basalt or iron-rich sedimentary rock

Indeterminate from photograph; likely fine-grained mafic rock (basalt) or ferruginous sandstone

Fossilized Bone Fragment

Vertebrate Fossil

Quartz in Matrix (possibly with Biotite or Hornblende)

Quartz (Silicon Dioxide, SiO2) in Granitic Matrix

Likely iron-rich rock or metallic mineral fragment

Uncertain; possibly limonite/goethite-rich material or weathered iron meteorite fragment

Honey calcite (likely rough cleavage fragment)

Calcite, calcium carbonate (CaCO₃)

Small gray rock fragment, likely granite or diorite

Uncertain; probable coarse-grained silicate rock dominated by feldspar and quartz, possibly biotite/hornblende

Tumbled or naturally etched mica-rich mineral specimen, likely muscovite

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂; possibly phlogopite mica

Weathered quartz-rich pebble

Mostly microcrystalline quartz (SiO₂), possibly quartzite or chalcedony with iron-oxide staining

Sandstone

Arenite (SiO2 based)

Likely weathered quartz-bearing rock fragment

Indeterminate granitic or quartz-rich silicate rock; chiefly quartz (SiO₂), possibly feldspar

Quartz Geode Fragment with Iron Staining

Silicon Dioxide (SiO2)

Likely metallic sulfide mineral fragment

Possibly galena (PbS) or pyrite (FeS₂); identification is uncertain from the photograph

Tumbled blue glassy mineral, possibly sodalite or blue aventurine

Identification uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) or blue-dyed quartz/slag-like material

Unidentified weathered rock, possibly quartz-bearing granite or rhyolite

Indeterminate; likely quartz–feldspar-rich silicate rock

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

Polished brecciated jasper

Silicified breccia, chiefly microcrystalline quartz (SiO₂) with iron-oxide staining

Quartz crystal fragment in weathered host rock

Quartz (SiO₂), possibly in a feldspathic or iron-stained matrix

Metallic sulfide-bearing rock, likely galena-rich ore

Galena (lead sulfide, PbS), possibly mixed with pyrite and host rock

Metallic sulfide ore, likely galena-bearing rock

Galena (lead sulfide, PbS), possibly with pyrite or other sulfides

Pale green translucent mineral fragment, likely calcite

Calcite (CaCO₃), tentatively; possibly green fluorite or prehnite

Tiny metallic mineral fragment, possibly native gold

Native gold (Au), unconfirmed; could also be pyrite or chalcopyrite

Black basalt (likely polished or cut fragment)

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase, clinopyroxene, and often olivine or magnetite

Likely quartz-rich rock fragment

Probably microcrystalline quartz (SiO₂), possibly a pale chert or quartzite fragment

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Likely pink feldspar-rich granite or pegmatite

Granite/pegmatite; primarily quartz (SiO₂), alkali feldspar (KAlSi₃O₈), and plagioclase feldspar

Pink chalcedony (likely rough agate/chalcedony)

Microcrystalline quartz, SiO₂; chalcedony variety, possibly iron-bearing

Brecciated jasper/chalcedony (iron-stained silica)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Small polished dark mineral or gemstone fragment

Indeterminate; possibly smoky quartz, obsidian, or dark tourmaline