Metamorphic Or Igneous (Context Dependent)

Blue Sapphire

Corundum (Al2O3)

Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Red cut gemstone, likely synthetic ruby

Corundum (Al₂O₃); possibly lab-grown ruby or red glass imitation

Chert (Arrowhead/Projectile Point)

Microcrystalline Quartz (SiO2)

Rough Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Chert Nodules in Limestone

Microcrystalline Quartz (SiO2) in Carbonate Matrix

Blue faceted gemstone, likely synthetic sapphire or blue glass

Corundum (Al₂O₃) if sapphire; identity cannot be confirmed visually

Tumbled orange chalcedony or quartzite

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony; exact identification requires testing

Green fluorite-bearing matrix specimen

Fluorite (calcium fluoride, CaF₂), likely with quartz and altered carbonate/silicate matrix

Quartz (Iron-stained)

Silicon Dioxide (SiO2) with Iron Oxide impurities

Chert (flint) fragment

Microcrystalline quartz (SiO₂), commonly called chert; “flint” is a variety of chert

Quartz crystal (likely milky or clear quartz)

Quartz, silicon dioxide (SiO₂)

Bronze or iron-age decorated pottery sherd

Archaeological ceramic fragment; likely fired clay with impressed or molded decoration, not a natural rock

Glauconitic Sandstone (or Greenstone)

Glauconitic Sandstone with Quartz

Pink faceted gemstone, likely synthetic cubic zirconia or pink sapphire

Uncertain from image; possible zirconium dioxide (cubic zirconia, ZrO₂) or corundum (pink sapphire, Al₂O₃)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Bivalve Fossil (Clam)

Class Bivalvia (e.g., Mercenaria or similar genus), composed of CaCO3 (Aragonite/Calcite)

Fossiliferous Limestone with Crinoid Stem fragment

Calcite (CaCO3) containing Crinoidea fossils

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Ironstone Concretion (Moqui Marble type)

Ironstone Concretion (Fe2O3 with SiO2 core)

Green beryl gemstone (likely emerald or green beryl)

Beryl, Be₃Al₂Si₆O₁₈; green color from chromium/vanadium or iron

Ruby (Raw Corundum)

Corundum (Al2O3:Cr)

Polished brecciated agate/jasper

Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide and possibly jasper inclusions

Chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly weathered chert

Milky Quartz (Water-worn pebble/nodule)

Quartz (Silicon Dioxide - SiO2)

Amethyst (rough crystal)

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Sandstone (Water-worn Cobble)

Arenite (variable composition, primarily SiO2)

Ruby

Corundum (Al₂O₃) with Chromium (Cr)

Quartz (Iron-stained or Ferruginous)

Silicon Dioxide (SiO2)

Fossil shell fragment (likely bivalve)

Bivalvia indeterminate; shell material chiefly aragonite or calcite (CaCO₃)

Quartz geode or vuggy quartz vein fragment

Quartz (SiO₂), likely with minor iron oxides and host carbonate or silicate minerals

Black Jasper

Silicon dioxide (SiO2) with carbon/mineral inclusions

Milky Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Jade (Nephrite or Jadeite)

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)

Limestone

Calcium Carbonate (CaCO3)

Metal-rich sulfide ore, likely galena-bearing rock

Galena (PbS) with pyrite/chalcopyrite in a host rock; exact identification requires testing

Emerald in Matrix

Emerald (Beryllium Aluminum Silicate), Be3Al2(SiO3)6

Lepidolite

K(Li,Al)3(Al,Si,3O10)(F,OH)2

Quartz vein rock

Milky quartz with smoky quartz; chiefly silicon dioxide (SiO₂)

Brecciated jasper (polychrome jasper)

Silicified breccia composed mainly of microcrystalline quartz (SiO₂), with iron-oxide and clay/mineral impurities

Copper-oxide ore (malachite-bearing copper ore)

Malachite, Cu₂CO₃(OH)₂, with likely chrysocolla and iron-oxide minerals

Blue-green copper mineralized rock, likely chrysocolla-bearing sandstone or copper ore

Chrysocolla (hydrated copper aluminosilicate; approximate formula (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O), possibly with malachite and copper oxides in a sandstone host