Synthetic (Ceramic)

Specular Hematite with Quartz and Limonite

Hematite (Fe2O3) with Quartz (SiO2) and Limonite (FeO(OH)·nH2O)

Ironstone Concretion (Limonite/Goethite)

Ferruginous concretion (Fe2O3·nH2O)

Red gemstone ring, likely synthetic ruby or red spinel

Ruby: corundum (Al₂O₃); spinel: MgAl₂O₄; exact identity requires testing

Rounded sandstone pebble

Quartz-rich sandstone, likely arkose or lithic sandstone

Bronze or iron-age decorated pottery sherd

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

Porcelain Tile (Sandstone-look)

Man-made Ceramic (resembling Quartz-rich Sandstone)

Iron-rich rock, possibly limonite/goethite

Hydrated iron oxides/hydroxides, commonly limonite (FeO(OH)·nH₂O) with goethite (α-FeO(OH))

Ferruginous Sandstone

Clastic Sedimentary Rock (Iron-rich)

Red glassy cabochon, likely synthetic ruby or red glass

Uncertain; possible synthetic corundum (Al₂O₃, chromium-colored) or man-made glass

Limonite Concretion

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)wnH2O)

Diamond (or Cubic Zirconia)

Cubic Carbon (C) or Zirconium Dioxide (ZrO2)

Rainbow Hematite / Magnetic Hematite

Iron oxide (Fe2O3) - often synthetic/coated for beads

Blue-gray kyanite crystal

Kyanite, Al₂SiO₅

Milky Quartz

Silicon Dioxide (SiO2)

Lepidolite

K(Li,Al)3(Si,Al)4O10(F,OH)2

Star sapphire ring

Corundum (Al₂O₃), likely asteriated sapphire

Opalite

Synthetic Opalised Glass

Opalite

Synthetic Opalised Glass

Opalite

Synthetic opalescent glass

Asphalt / Road Aggregate

Bituminous Conglomerate (synthetic)

Opalite

Synthetic Opalized Glass

Likely weathered sandstone or iron-stained sedimentary pebble

Indeterminate clastic sedimentary rock; possibly quartz-rich sandstone

Pink feldspar crystal

Likely potassium feldspar (orthoclase or microcline), KAlSi₃O₈

Likely blue-green kyanite

Kyanite, Al₂SiO₅

Tumbled feldspar-rich rock, likely pink-orange microcline or granite fragment

K-feldspar (microcline/orthoclase), approximately KAlSi₃O₈; exact identification requires testing

Feldspar (Plagioclase / Orthoclase)

KAlSi3O8 / CaAl2Si2O8 - NaAlSi3O8

Lepidolite on Pegmatite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2) in Granitic Pegmatite

Limonite

FeO(OH)·nH2O

Likely weathered limestone or calcareous tuff

Calcite-rich carbonate rock, chiefly CaCO₃; exact identification is uncertain from the image

Ferruginous Sandstone (Ironstone)

Clastic sedimentary rock (SiO2 with Fe2O3/FeO(OH) cement)

Ruby (set in a ring; possibly synthetic or imitation)

Corundum, Al₂O₃; red color is typically caused by chromium

Iron-rich sandstone or lateritic ironstone pebble

Ferruginous sandstone/ironstone, composed mainly of quartz (SiO₂) and iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

Tumbled dark-blue stone, possibly sodalite or dyed stone

Likely sodalite (Na₈Al₆Si₆O₂₄Cl₂); exact identification requires testing

Weathered granitic rock fragment

Likely granite or granodiorite, chiefly quartz, feldspar, and minor biotite/hornblende

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Faceted Clear Gemstone (Likely Quartz or Cubic Zirconia)

Silicon Dioxide (SiO2) or Zirconium Dioxide (ZrO2)

Magnetic Hematite (Man-made)

Iron Oxide (Fe2O3) with Barium-Strontium Ferrite

Porcelain (Stoneware Ceramic)

Mullite / Silica-glass composite (Al6Si2O13)

Faceted Quartz or Cubic Zirconia

SiO2 (Quartz) or ZrO2 (Cubic Zirconia)

Tumbled coral fragment (likely white calcitic coral)

Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image

Limonite

Hydrous ferric oxides (FeO(OH)·nH2O)