Sedimentary Or Metamorphic Derived

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Mica Schist (with Muscovite)

Muscovite Mica Schist (KAl2(AlSi3O10)(F,OH)2)

Quartzite

Quartzite (mostly SiO2)

Rhodonite

Manganese silicate: (Mn,Fe,Mg,Ca)SiO3

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Quartz-rich limestone or calcitic marble

Calcite (CaCO₃), possibly with quartz (SiO₂)

Yellow Aventurine

Silicon Dioxide with inclusions (SiO2 + Muscovite/Fuchsite)

Small weathered mineral/rock fragment

Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen

Mica Schist

Mica Schist (primarily Muscovite and Quartz)

Hematite

Iron(III) oxide (Fe2O3)

Rounded dark metamorphic pebble

Likely mica schist or chlorite-rich greenschist; exact identification requires testing

Rounded quartz-rich cobble

Likely quartzite or quartz-rich sandstone; exact identification requires a fresh break or hardness test

Carnelian Agate

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Fuchsite Gneiss or Schist

Muscovite (variety Fuchsite) within Metamorphic Host Rock

Mica Schist

Schist (Muscovite-Quartz Schist)

Marble

Recrystallized Calcite (CaCO3)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Mixed river-worn rock and mineral collection

Mostly quartz/quartzite, feldspar-bearing granitoid, chert, and mafic volcanic rocks; exact species vary by pebble

Orange Calcite

Calcium Carbonate (CaCO3)

Schist (Micaceous)

Mica Schist (predominantly Muscovite or Biotite)

Small weathered quartz-rich pebble

Likely quartz (SiO₂), possibly quartzite or feldspar-bearing rock

Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Blue Quartz

Silicon Dioxide (SiO2) with microscopic inclusions

Polished blue stone, likely sodalite

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; possibly blue-dyed jasper or lapis lazuli

Green Aventurine

Silicon Dioxide with Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Tumbled greenstone-like pebble

Likely serpentine or chlorite-rich metamorphic rock; exact identification requires testing

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Weathered quartz-rich river cobble, possibly quartzite

Quartzite (mostly microcrystalline SiO₂), tentatively identified

Yellow Aventurine

Quartzite with Muscovite/Goethite inclusions (SiO2)

Water-worn pebble, likely quartzite

Quartzite (predominantly recrystallized quartz, SiO₂); identification from the image is tentative

Carnelian

Carnelian (SiO2 variant)

Blue Quartz (Dumortierite Quartz)

Silicon Dioxide (SiO2) with inclusions of Dumortierite (Al7BO3(SiO4)3O3)

Rounded gray metamorphic pebble, likely quartzite or gneiss

Quartzite (quartz-rich rock) or fine-grained gneiss; exact identification requires testing

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Gold-colored mineral specimen, likely pyrite or weathered mica schist

Tentatively pyrite (FeS₂); identification is uncertain from the obscured image

Rounded quartz-rich pebble

Likely quartzite or quartz-bearing granitoid; predominantly SiO₂ quartz with possible feldspar and mica

Red Aventurine (Strawberry Quartz)

Silicon Dioxide (SiO2) with inclusions of Hematite or Goethite

Dark gray rock fragment (tentative basalt or slate)

Indeterminate; possibly fine-grained basalt, or metamorphic slate

Rounded quartz-rich pebble, possibly weathered granite or quartzite

Indeterminate; likely quartz (SiO₂)-rich silicate rock