Mineralogical Specimen

Gypsum (likely selenite/alabaster)

Gypsum, CaSO₄·2H₂O

Rutilated quartz (likely a cabochon set in metal)

Quartz, SiO₂, containing rutile inclusions (TiO₂)

Iron-stained chert (possible jasper)

Microcrystalline quartz (SiO₂), likely iron-oxide stained

Unknown small pale rock fragment

Unidentified light-colored granular mineral aggregate; likely quartz-rich material or limestone

Banded agate (chalcedony)

Microcrystalline quartz (SiO₂), variety chalcedony

Likely weathered metamorphic rock (possibly schist or gneiss)

Indeterminate; probable mica-rich quartz–feldspar metamorphic rock

Limonite

FeO(OH)•nH2O

Likely tumbled or polished fossil shell

Fossilized mollusk shell; exact species cannot be determined from this image

Bivalve Fossil (Shell-bearing Sedimentary Rock)

Class Bivalvia (Phylum Mollusca) within a Calcarenite/Sandstone matrix

Iron-stained quartz-rich rock

Likely ferruginous quartzite; chiefly quartz (SiO₂) with iron oxides/hydroxides

Weathered iron-rich rock, possibly limonite-bearing basalt or ironstone

Indeterminate; likely basaltic or ferruginous rock containing iron oxides/hydroxides such as hematite (Fe₂O₃) and limonite/goethite

Quartz with Epidote

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate [Ca2(Al,Fe)3(SiO4)3(OH)]

Chert (with Desert Varnish/Iron Stain)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chalcedony (Desert Rose or Botryoidal Chalcedony)

Silicon Dioxide (SiO2)

Diamond (Cut Specimen)

Carbon (C)

Travertine (Tufa)

Chemical Sedimentary Rock / Travertine (CaCO3)

Orthoclase (Potassium) Feldspar in Quartz

KAlSi3O8 (Potassium Aluminum Silicate)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with impurities of iron)

Sandstone

Arenite (SiO2 based)

Weathered quartz-rich pebble, possibly granitic gneiss

Quartz–feldspar–mica aggregate; likely granitoid or gneiss

Limonite

FeO(OH)·nH2O

Pink-gray granite

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Granite

Granite, a coarse-grained intrusive felsic rock composed mainly of quartz, feldspar, and mica

Clear Quartz (Rock Crystal) Bead

Silicon Dioxide (SiO2)

Biotite (Black Mica)

Biotite (K(Mg,Fe++)3AlSi3O10(OH,F)2)

Galena-bearing sulfide specimen

Galena (PbS), likely with sphalerite and/or pyrite gangue

Silver (Native Element)

Ag (Argentum) - 90% Silver, 10% Copper alloy in specimen

Conglomerate

Sedimentary Conglomerate with Basaltic Clast

Dark gray crystalline rock, possibly mica-rich schist or graphite-bearing gneiss

Indeterminate; likely quartz–feldspar–mica metamorphic rock

Yellow Quartz Pebble

Quartz (Silicon Dioxide - SiO2)

Polished labradorite

Labradorite, a plagioclase feldspar in the albite–anorthite series (approximately (Ca,Na)(Al,Si)₄O₈)

Basalt River Cobble

Basalt (Aphanitic Mafic Volcanic Rock)

Rough Quartz (or Quartzite pebble)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

White tumbled stone, possibly quartz or marble

Unidentified; appearance alone cannot distinguish quartz (SiO₂) from calcite-rich marble (CaCO₃).

Blue-gray stone fragment, possibly slate or fine-grained basalt

Undetermined; appearance is consistent with slate (fine-grained metamorphosed mudstone), but the image is insufficient for reliable identification.

Tumbled jasper

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions

Fossiliferous Limestone or Shale

Biomicrite (if limestone) or Fossiliferous Shale

Tumbled orange feldspar (likely sunstone or orange aventurine)

Alkali feldspar, commonly orthoclase or microcline; approximate composition KAlSi₃O₈

Polished dendritic agate cabochon

Microcrystalline quartz (chalcedony), SiO₂, with iron/manganese dendrites and possible plume inclusions

Likely rough pink feldspar or rose quartz

Most likely microcline feldspar (KAlSi₃O₈) or rose quartz (SiO₂)

Granite

Granite (Phaneritic Quartz-Feldspar rock)