Metamorphic Or Igneous Alteration

Serpentinite

Serpentinite (Hydrated magnesium iron phyllosilicate)

Greenstone with Pyrite inclusions

Greenschist / Meta-volcanic rock with Iron Disulfide (FeS2)

Epidosite (Epidote-rich rock)

Epidotalite (primarily Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH))

Auriferous Quartz (Gold-bearing Quartz)

Silicon Dioxide (SiO2) with trace Gold (Au) and Iron Oxides

Milky Quartz

Silicon Dioxide (SiO2)

Greenstone

Metabasalt / Greenstone (low-grade metamorphic rock)

Milk Quartz (White) and Yellow Aventurine (Yellow)

Silicon Dioxide (SiO2)

Hematite

Ferric Oxide (Fe2O3)

Pyrite

Iron Sulfide (FeS2)

Hematite

Iron(III) oxide (Fe2O3)

Yellow Sapphire

Corundum (Al2O3)

Yellow Sapphire

Corundum (Al2O3)

Possible hematite-rich ironstone or magnetite-bearing specimen

Likely hematite (Fe₂O₃), magnetite (Fe₃O₄), or an iron-rich slag-like geological specimen

Tumbled Ruby

Corundum (Al2O3:Cr)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Ruby / Red Tourmaline

Corundum (Al2O3) or Elbaite (Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)4)

Star Ruby

Corundum (Al2O3 with chromium and rutile inclusions)

Sapphire

Corundum (Al2O3)

Weathered greenish stone, possibly serpentinite or altered basalt

Tentatively serpentinite (mostly serpentine minerals) or chlorite-rich basalt; exact identification requires testing

Green Aventurine

Quartz with Fuchsite inclusions (SiO2)

Tumbled purple stone, likely charoite

Charoite, a complex potassium-calcium silicate mineral (commonly approximated as (K,Sr,Ba,Mn)₁₅–₁₆(Ca,Na)₃₂Si₇₀O₁₈₀(OH,F)₄·nH₂O)

Serpentine

Antigorite, Lizardite, or Chrysotile; (Mg,Fe)3Si2O5(OH)4

Epidote in Quartz

Epidote (Ca2(Al,Fe)3(SiO4)3(OH)) in Milky Quartz (SiO2)

Unakite

Unakite (Epidotized Granite)

Aquamarine (Beryl) Beads

Beryllium aluminum silicate (Be3Al2Si6O18)

Greenstone / Epidosite

Epidosite (Metasomatic rock consisting mainly of Epidite Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH) and Quartz)

Greenstone / Greenschist

Greenschist facies metamorphic rock (composed primarily of chlorite, actinolite, and epidote)

Milky quartz (possible pale green quartz)

Quartz, silicon dioxide (SiO₂)

Serpentine Pebble

Serpentine ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)

Greenstone

Metabasalt / Greenschist

Weathered quartz-bearing rock, possibly calcite vein fragment

Indeterminate; likely quartz (SiO₂) with carbonate minerals such as calcite (CaCO₃)

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Quartz vein rock (milky quartz)

Milky quartz, SiO₂; likely quartz-rich vein material in altered host rock

Tumbled epidote-bearing granite or amphibolite

Quartz–feldspar rock with dark amphibole/biotite and epidote; exact identification is uncertain from the image

Quartz in Matrix (or Quartz Vein Rock)

Silicon Dioxide (SiO2) with host rock

Quartz-rich feldspathic rock, possibly weathered granite or quartzite

Likely quartz and feldspar aggregate; exact identification is uncertain from the photograph

Greenstone / Epidosite

Epidosite (primary minerals: Epidote and Quartz)

Yellow Aventurine (specifically a carved crescent moon)

Silicon Dioxide (SiO2) with inclusions

Hematite

Iron(III) oxide (Fe2O3)

Orange Aventurine / Quartz

Silicon Dioxide (SiO2) with Hematite or Goethite inclusions

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica, possibly with gneissic foliation