Sedimentary Or Metamorphic Derived

Beach Pebbles and Quartz Aggregates

Quartz pebbles and biogenic fragments (SiO2, CaCO3)

Polished septarian nodule cabochon

Septarian calcite–aragonite nodule, commonly in a clay-rich limestone/marl matrix

Marble

Marble (metamorphosed limestone or dolostone), primarily composed of calcite (CaCO3) or dolomite (CaMg(CO3)2)

Road-surface aggregate (crushed stone)

Unidentifiable mixed lithic aggregate; likely basaltic/andesitic fragments with feldspar, quartz, and weathered rock

Coal

Bituminous Coal / Anthracite

Fuchsite

Chromium-rich Muscovite (KAl2(AlSi3O10)(OH,F)2 with Cr replacements)

Lazulite

Magnesium Aluminum Phosphate Hydroxide (MgAl2(PO4)2(OH)2)

Seraphinite (Clinochlore)

Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8

Pyrite-bearing rock, possibly pyrite-rich schist or quartzite

Pyrite (iron disulfide, FeS₂) in a fine-grained metamorphic or quartz-rich matrix

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions) - SiO2

Hematite

Iron Oxide (Fe2O3)

Schist

Crystalline Metamorphic Rock (Schistose)

Schist

Mica Schist (primarily composed of quartz, feldspar, and mica)

Quartz

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, likely chert or quartzite

Quartzite/chert; predominantly microcrystalline quartz (SiO₂), with iron-oxide staining and possible minor feldspar or clay minerals

White quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂)

Coarse sand with a small pebble

Unconsolidated siliciclastic sediment, chiefly quartz and rock fragments

Brown quartz-rich pebble (likely chert or weathered quartzite)

Quartz (SiO₂), possibly microcrystalline quartz/chert or quartzite

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Green Quartzite

Silicon Dioxide (SiO2) with inclusions (e.g., Fuchsite or Actinolite)

Polished operculum (“Shiva eye” shell)

Calcium-carbonate shell operculum, commonly from a turban snail (family Turbinidae); not a mineral specimen

Fuchsite in Quartz

K(Al,Cr)2(AlSi3O10)(OH)2 + SiO2

Quartz Vein in Matrix (Breccia / Host Rock with Quartz)

Silicon Dioxide (SiO2) in Host Rock Matrix

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Potassium Feldspar

Orthoclase (KAlSi3O8)

Biotite Schist

Biotite Schist (containing K(Mg,Fe)3AlSi3O10(OH)2)

Ruby in Zoisite

Anyolite (Zoisite with Corundum)

Schist (Garnet-Mica Schist)

Garnet-Mica Schist

Tumbled chalcedony (likely milky quartz)

Microcrystalline quartz, SiO₂; possibly pale agate or quartzite

Faceted clear gemstone, likely glass or cubic zirconia

Undetermined; could be synthetic cubic zirconia (ZrO₂) or cut glass (silica-based)

Milky Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Limonite pseudomorph after Pyrite

Goethite/Limonite FeO(OH)·nH2O

Pyrite-bearing rock (iron pyrite)

Pyrite, FeS₂, likely disseminated or massive in a host rock

Epidote in Quartz (Unakite-like specimen)

Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Quartz (SiO2)

Polished banded river stone

Likely foliated gneiss or banded metamorphic rock; exact identification requires a fresh surface or testing

Serpentinite (serpentinized ultramafic rock)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with magnetite, brucite, and residual olivine/pyroxene

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Green chalcedony (possibly chrysoprase) cabochon

Chalcedony, microcrystalline quartz (SiO₂); chrysoprase is nickel-colored chalcedony

Carnelian (Red Agate)

Carnelian (SiO2 with Hematite inclusions)

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Chert (Carnelian/Jasper variety)

Microcrystalline Quartz (SiO2)