Mineral, Possibly Rock Fragment Containing A Mineral

Quartz-rich rock fragment, possibly granite or quartzite

Primarily quartz (SiO₂), with possible feldspar and iron-oxide staining

Granite fragment

Granite

Metallic sulfide ore fragment, possibly pyrite-bearing rock

Indeterminate; likely pyrite (FeS₂) in a sulfide-rich matrix

Quartz-rich rock fragment

Microcrystalline quartz (SiO₂), possibly chalcedony or quartz-bearing breccia

Weathered fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Banded agate or jasper fragment

Microcrystalline quartz, SiO₂ (likely iron-stained chalcedony)

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment

Weathered iron-rich rock, possibly laterite or limonite-bearing stone

Hydrated iron oxides/hydroxides, chiefly limonite-goethite mixture; exact identification requires testing

Unidentifiable Rock Fragment

Uncertain small metallic-looking mineral/rock fragment

Indeterminate; possibly galena-bearing rock or metallic slag

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂), colored by hematite/goethite; possibly brecciated jasper

Weathered quartz-rich pebble (tentative)

Likely quartz/chalcedony, SiO₂, possibly iron-stained

Quartz Pebble (Geode Fragment / Druzy Cavity)

Silicon Dioxide (SiO2)

Quartz-rich breccia or vein quartz fragment

Quartz (SiO₂), likely with iron-oxide staining and attached host rock

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Unidentifiable Specimen

Undetermined

Likely weathered metallic mineral or slag fragment

Indeterminate; possibly iron-rich sulfide/oxide material or industrial slag

Weathered iron-rich rock fragment

Likely limonite/goethite-rich ironstone; exact identification requires testing

Weathered iron-rich rock, possibly laterite or limonite-bearing sandstone

Laterite/limonite-rich material; commonly dominated by goethite (FeO(OH)) and hydrated iron oxides

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Weathered tan mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar-rich rock, or limonite-bearing material

Fossiliferous limestone, possibly containing a brachiopod or bivalve fossil

Calcite-rich limestone (CaCO₃), with an apparent shell impression or shell fragment

Weathered sandstone or volcanic rock fragment

Indeterminate; likely quartz–feldspar-rich sandstone, possibly altered volcanic rock

Fossiliferous Limestone

Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)

Light-colored weathered stone, possibly limestone or quartz-rich rock

Indeterminate; likely calcitic limestone (mostly CaCO₃) or quartz sandstone (SiO₂)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica (possibly gneissic if foliation is confirmed)

Quartz-rich rock, possibly milky quartz or quartzite fragment

Quartz (SiO₂), potentially quartzite if metamorphic

Small quartz-rich pebble

Quartz (SiO₂), possibly quartzite or weathered granite fragment

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

Weathered greenish rock fragment

Indeterminate; possibly epidote- or chlorite-bearing altered silicate rock

Iron-rich weathered stone, possibly limonite/goethite

Limonite (mixture of hydrated iron oxides), commonly goethite (α-FeO(OH))

Iron-rich brown stone, possibly weathered chert or ironstone

Undetermined; likely iron-oxide-bearing silica-rich rock (chert/ironstone)

Weathered quartz-rich rock fragment

Indeterminate; possibly weathered granite, quartzite, or rhyolite

Pebble

Clast (specifically a granule or small pebble)

Pale green translucent mineral fragment

Indeterminate; possibly fluorite, calcite, or glassy quartz

Polished brown mineral fragment, likely quartz-rich iron-stained material

Possibly quartz (SiO₂) with iron-oxide inclusions; exact identification is uncertain from the image

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Tumbled brecciated jasper

Silica-rich microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions

Chert (Nodule / Geode fragment)

Microcrystalline Quartz (SiO2)

Quartz (Quartzite fragment)

Silicon Dioxide (SiO2)

Limestone with Fossil Imprints

Biogenic Limestone (Calcium Carbonate, CaCO3)

Likely milky quartz fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide or mica inclusions