Industrial Byproduct (Anthropogenic Material)

Emerald (Rough)

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Dalmatian jasper

Orbicular rhyolite, commonly marketed as Dalmatian jasper; quartz–feldspar volcanic rock with dark aegirine/arfvedsonite-like inclusions

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Diamond (Cut and Polished)

Carbon (C)

Basalt

Basalt

Diamond

Native Carbon (C)

Chalcedony

Cryptocrystalline Quartz (SiO2)

Tumbled yellow calcite

Calcite (calcium carbonate, CaCO₃)

Chert (specifically Red Chert/Jasper nodule)

Microcrystalline Quartz (SiO2)

Chert (potentially Jasper/Common Opal mixture)

Microcrystalline Quartz (SiO2)

Small polished pink-and-white mineral pebble

Likely rose quartz or pale pink quartz; exact identification is uncertain from the image

Weathered iron-rich concretion or laterite fragment

Ferruginous concretion, likely goethite/limonite (hydrated iron oxides) in a clay-rich matrix

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

Olivine (Peridot)

Magnesium Iron Silicate ((Mg, Fe)2SiO4)

Quartzite Pebble

Quartzite (predominantly Silicon Dioxide - SiO2)

Crackle Quartz (Dyed)

SiO2 (Silicon Dioxide) - Treated

Olivine in Quartz/Feldspar Matrix (Peridotite or Granitic Pegmatite)

(Mg,Fe)2SiO4 (Olivine) with Quartz / Feldspar

Orange Calcite

Calcium Carbonate (CaCO3)

Epidote in Matrix

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

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Raw Diamond

Diamond (pure Carbon, C)

Chert (often called Flint when dark or worked)

Cryptocrystalline silica (SiO2)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Tumbled smoky quartz with iron-stained inclusions

Quartz (SiO₂), likely smoky quartz variety

Rhodonite

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

Chert / Flint

Microcrystalline quartz (SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)

Polished red jasper

Jasper, a microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides

Greywacke (River Pebble)

Greywacke sandstone with quartz veining

Diabase (Greenstone)

Diabase (also known as Dolerite)

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Vesicular quartz-rich rock, possibly weathered rhyolite or silicified volcanic breccia

Silica-rich volcanic rock; likely microcrystalline quartz (SiO₂) with altered feldspar and iron-oxide staining

Blue Aragonite

Aragonite (Calcium Carbonate, CaCO3)

Rough Ruby

Corundum (Al2O3) with Chromium traces

Diamond (Cut jewelry specimen)

Diamond (pure Carbon, C)

Rutilated Quartz

Quartz (SiO2) with Rutile (TiO2) inclusions

Polished green aventurine

Quartzite dominated by quartz (SiO₂), colored by fuchsite mica and/or iron-bearing inclusions

Galena-rich sulfide specimen

Galena (lead sulfide, PbS), possibly with sphalerite and oxidized sulfides

Diamond

Carbon (C)

Tumbled azurite–malachite or blue jasper (tentative)

Likely azurite-bearing copper mineral aggregate; composition commonly Cu₃(CO₃)₂(OH)₂ with associated malachite Cu₂CO₃(OH)₂