Sedimentary Or Metamorphic Derived

Yellow Quartz (Citrine Quartz)

Silicon Dioxide (SiO2)

Citrine

Silicon dioxide (SiO2)

Layered dark metamorphic rock, likely slate or phyllite

Slate/phyllite; predominantly fine-grained quartz, mica, and chlorite

Red Jasper

Jasper (Silicon Dioxide Si₂O₃)

Schist

Mica Schist

Dark gray rounded river pebble

Likely basalt or fine-grained volcanic rock; exact identification requires testing

Yellow Beryl

Beryl (Be3Al2(SiO3)6)

Green Aventurine (Fuchsite-bearing Quartz)

Silicon Dioxide with Chromium-rich Muscovite (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Likely weathered quartzite pebble

Quartzite, predominantly SiO₂

Quartz Vein in Sedimentary Matrix

Silicon Dioxide (SiO2) with host rock

Garnet

Garnet Group (e.g., Almandine, Pyrope)

Rhodonite

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

Native Silver Nugget

Silver (Ag)

Tumbled hematite (likely hematite-rich ironstone)

Hematite, Fe₂O₃; possibly mixed with magnetite or goethite

Banded river pebble, likely gneiss

Foliated quartz–feldspar rock, possibly banded gneiss

Serpentine (likely serpentinized ultramafic rock)

Serpentinite; chiefly antigorite, lizardite, or chrysotile Mg₃Si₂O₅(OH)₄, often with magnetite and relict olivine/pyroxene

Polished serpentine (likely)

Serpentine-group minerals, chiefly antigorite and lizardite; commonly derived from altered peridotite

Fuchsite in Quartz

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Quartz (SiO2)

Rounded granitic gneiss cobble

Foliated quartz–feldspar–mica gneiss; likely granitoid-derived

Banded gneiss (likely biotite-rich gneiss)

Gneiss; chiefly quartz, feldspar, biotite, and possibly hornblende

Ruby in Zoisite (Anyolite)

Ruby-Zoisite

Rhodonite

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

Pyrite-bearing metamorphic rock (likely schist or quartzite)

Mica/quartz-rich metamorphic matrix with pyrite (FeS₂), possibly chalcopyrite (CuFeS₂)

Natural freshwater pearls

Pearl (nacreous calcium carbonate; chiefly aragonite, CaCO₃)

Mica Schist with Pyrite

Muscovite/Biotite Schist with Iron Sulfide (FeS2)

Green Aventurine

Silicon dioxide (SiO2) with fuchsite inclusions

Pyrite

Iron Disulfide (FeS2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides

Flint

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert / Flint (or lithic artifact flake)

Microcrystalline Quartz (SiO2)

Greenstone (Epidote/Chlorite Rich Rock)

Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))

Painted River Rock

Painted Quartzite or Smooth Siltstone

Mica Schist

Mica Schist (primarily Muscovite or Biotite within a foliated matrix)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Quartz Vein in Host Rock (Likely Slate or Shale)

Hydrothermal Quartz (SiO2) in Pelitic host rock

Red Jasper

Jasper (Silicon Dioxide, SiO2)

Red Jasper

Jasper (Silicon Dioxide with Iron inclusions - SiO2)

Weathered quartz-rich pebble

Likely quartzite or quartz-rich sandstone; exact identification is uncertain from the photograph

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite