Mineral, Possibly Rock Fragment Containing A Mineral

Vesicular basalt (likely weathered volcanic rock)

Vesicular basalt; predominantly plagioclase, pyroxene, and possibly olivine, with secondary zeolite or calcite infill

Fossiliferous limestone

Bioclastic carbonate rock, chiefly calcite (CaCO₃)

Small brown mineral/rock fragment

Indeterminate; possibly weathered quartz-rich rock, ironstone, or a sulfide mineral

Weathered dark mineral/rock fragment

Indeterminate; possibly iron-rich basalt, slag, or a sulfide-bearing mineral

Pale green-gray stone, possibly serpentinite

Serpentinite (rock composed mainly of serpentine-group minerals)

Conglomeratic breccia (possibly polymictic volcanic breccia)

Polymictic breccia; clasts in a fine-grained volcanic or sedimentary matrix

Mixed mineral and rock specimen collection

Mixed assemblage, visibly including quartz, chalcedony/agate, feldspar, mica, dark mafic rocks, and possibly calcite or gypsum

Likely quartz-bearing rock fragment

Quartz (SiO₂), possibly with iron-oxide staining or other mineral inclusions

Unknown Rock Fragment

Unknown

Weathered quartz-rich rock, likely granite or quartzite

Indeterminate; probable quartz–feldspar aggregate, possibly granitic gneiss

Dark mineral-rich rock fragment

Indeterminate; possibly dark quartzite, chert, or weathered igneous rock

Quartz-bearing gray rock, likely druzy quartz in host rock

Quartz (SiO₂), possibly in a chert, chalcedony, or fine-grained volcanic host

Unidentified pale mineral or rock surface

Indeterminate from image; possibly a small quartz or feldspar grain

Small rounded mineral pebble, possibly feldspar or quartz

Uncertain from image; likely a quartz- or feldspar-rich grain

Quartz Geode Fragment with Iron Staining

Silicon Dioxide (SiO2)

Weathered yellow-brown rock pebble

Undetermined; possibly iron-oxide-stained sandstone or mudstone

Likely weathered brown rock fragment

Indeterminate; possibly iron-oxide-stained sandstone or laterite

Fossilized Bone Fragment

Vertebrate Fossil

Likely rough quartz fragment

Quartz (SiO₂), possibly iron-stained or included quartz

Likely dark mineral or rock fragment

Indeterminate from image; possibly a dark silicate mineral such as hornblende, biotite, or basalt

Quartz-bearing sulfide ore (possibly galena in a quartz matrix)

Likely galena (PbS) with quartz (SiO₂); identification is uncertain from the image alone

Uncertain small pale mineral fragment

Indeterminate; possibly calcite or a light-colored feldspar fragment

Mixed mineral and shell specimen assortment

Primarily unidentified quartz-/feldspar-like pebbles with possible dark basalt or iron-rich fragments; white pieces may include shell or calcite

Banded sandstone

Quartz-rich sandstone (quartz arenite or feldspathic sandstone; exact type cannot be determined from the image)

Small banded metamorphic rock fragment

Indeterminate foliated metamorphic rock; possibly mica schist or gneiss

Brecciated jasper, possibly rainforest jasper

Jasper: microcrystalline to cryptocrystalline quartz, SiO₂, commonly containing hematite, goethite, chlorite, epidote, and other iron- and manganese-bearing minerals

Coquina or Fossiliferous Sandstone

Fossiliferous Calcarenite (CaCO3 with SiO2 inclusions)

Limestone with Fossil Inclusion

Calcium Carbonate (CaCO3)

Unidentified brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or weathered limonite

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Fossiliferous limestone, possibly containing a brachiopod or bivalve fossil

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

Fossilized wood or bone fragment

Indeterminate permineralized organic fossil; possibly silicified wood or fossil bone

Weathered quartz-rich rock, possibly quartzite

Quartzite (mostly SiO₂), though a feldspathic sandstone or weathered granite fragment is also possible

Small weathered fossil or mineral fragment

Indeterminate; possibly fossilized shell, bone, or a pale carbonate mineral

Tiny amber-colored crystal fragment

Indeterminate; possibly quartz, feldspar, mica, or a sulfide mineral

Dark, coarse-grained rock (possibly diorite or amphibolite)

Undetermined; likely a mafic to intermediate rock containing plagioclase and dark amphibole or pyroxene

Small weathered mineral/rock fragment

Uncertain from image; possibly quartz-rich sandstone or a feldspar-bearing rock

Weathered rock fragment (likely granite or granitic gneiss)

Undetermined felsic rock; possibly quartz–feldspar granite

Conglomeratic basalt (rounded volcanic breccia/pebble)

Basaltic conglomerate or polymict volcanic breccia; predominantly plagioclase–pyroxene basalt with lighter felsic or weathered clasts

Mixed collection of quartz-rich rocks and minerals

Quartz (SiO₂), with some pieces possibly containing feldspar or mica; exact identification is uncertain from the image

Unidentified orange-brown rock fragment

Likely weathered iron-rich volcanic rock or ochre-bearing material; exact identification is impossible from the blurred image

Fossiliferous limestone, possibly a shell or bone fragment

Calcitic limestone; predominantly calcium carbonate (CaCO₃), likely calcite