Sedimentary Or Metamorphic (Base Substrate)

Yellow Aventurine

Silicon Dioxide with inclusions (SiO2 + Muscovite/Fuchsite)

Rounded quartz-rich cobble

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

Gneiss (Augen Gneiss)

Augen Gneiss

Quartz Vein in Sedimentary Matrix

Silicon Dioxide (SiO2) with host rock

Gold Mineral

Native Gold (Au)

Dragon Blood Jasper

Epidote with Red Piedmontite (Chalcedony/Quartz variant)

Gneiss (River Cobble)

Gneiss

Titanium Quartz (Aura Quartz)

Silicon Dioxide (SiO2) treated with Titanium

Amethyst and Gravel Collection

Amethyst (Silicon Dioxide, SiO2)

Anthracite Coal

Anthracite (Carbon-based metamorphic rock)

River Pebble (Gneiss/Schist mix)

Metamorphic rock aggregate

Granitoid Gneiss with Feldspar Vein

Gneiss (High-grade Metamorphic Rock) with Potassium Feldspar (KAlSi3O8)

Greenschist

Greenschist (composed mainly of chlorite, epidote, actinolite, and albite)

Graphite

Graphite (C)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Probable mica schist

Schist, likely muscovite–biotite schist

Pyrite-bearing schist (likely mica schist)

Muscovite–quartz schist with disseminated pyrite (FeS₂)

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Gneiss

Gneiss

Granite Gneiss

Granitoid Gneiss

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Gneiss

Gneiss (Foliated Metamorphic Rock)

Gneiss

Gneiss (High-Grade Metamorphic Rock)

Quartzite River Rock

Quartzite (primarily SiO2)

Shungite

Non-crystalline carbon (allotrope of carbon)

Petrified Wood with Lichen

Silicified Wood (SiO2) colonized by crustose lichens

Chert with Asphaltum (or Tar)

Silica (SiO2) with natural Bitumen/Asphaltum

Sandstone with Liesegang Rings

Quartzose Sandstone with Iron Oxide Precipitation

Iolite (Cordierite)

Magnesium Iron Aluminum Silicate (Mg,Fe)2Al4Si5O18

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Gneiss

Gneiss (SiO2-rich metamorphic rock)

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

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

Yellow Quartz River Pebble

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartzite Pebbles with Quartz Veining

SiO2 (Silicon Dioxide with country rock matrix)

Epidote with Quartz Vein

Epidote-bearing metamorphic rock with quartz (Ca2(Al,Fe)3(SiO4)3(OH))

Gneiss (Metamorphosed Granitic Rock)

Gneiss (composed mainly of quartz, feldspar, biotite, and/or hornblende)

Gneiss

Gneiss

Banded Gneiss

Gneiss (Felsic to Mafic Metamorphic Rock)

Anthracite Coal

Anthracite (Carbon-based sedimentary-metamorphic rock)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Native Silver Nugget

Silver (Ag)

Tumbled hematite (likely hematite-rich ironstone)

Hematite, Fe₂O₃; possibly mixed with magnetite or goethite