Mineral (Silicate Replaced Organic Material)

Jasper Agate

Silicon dioxide (SiO2)

Fossilized Gastropod Shell

Gastropoda (Fossilized internal mold or shell body)

Sandstone

Sandstone (Quartz-rich Arenite / SiO2)

Shark Tooth Fossil

Selachii fossil

Petrified Wood

Silicified Wood (SiO2)

Brachiopod Fossil

Phylum Brachiopoda

Fossilized Brain Coral

Diploria labyrinthiformis (Fossilized)

Fossil Shark Tooth

Lamniform (Mackerel Shark) fossil tooth, likely Otodus or Cretalamna

Jasper / Chert (Red)

Cryptocrystalline quartz (SiO2)

Fossil Coral (Honeycomb Coral)

Favosites (extinct genus of Tabulate coral)

Shark Tooth Fossil

Elasmobranchii dentition (fossilized)

Likely sandstone or weathered quartz-rich rock fragment

Quartz-rich sandstone; exact identification is uncertain from the photograph

Chert (Flint)

Microcrystalline Quartz (SiO2)

Unakite (bottom) and Sodalite (top)

Epidotized Granite (Unakite) and Sodium Aluminum Silicate Chloride (Sodalite)

Sandstone (Ferruginous)

Arenite (with iron oxide cement)

Tiger's Eye (Multicolor/Variegated)

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxides)

Fossilized Coral in Chert

Anthozoa (Class) fossil in Cryptocrystalline Quartz (SiO2)

Diorite (or Gabbro/Gneiss stream pebble)

Diorite

Quartz with impurities or Host Rock

SiO2 (Silicon Dioxide) with mixed silicates

Polished brecciated jasper

Brecciated jasper, an opaque microcrystalline quartz aggregate (SiO₂) with iron-oxide staining and cement

Polished brecciated jasper (likely orbicular/picture jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide staining and breccia fragments

Plum Blossom Tourmaline

Tourmaline with Lepidolite (Na,Ca)(Li,Mg,Al)3Al6(BO3)3Si6O18(OH)4

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Limonite (Ironstone)

Limonite (mixture of hydrated iron(III) oxide-hydroxides)

Pyrite

Iron Sulfide (FeS2)

Pyrite Geode

Iron Disulfide (FeS2)

Serpentinite-bearing quartz vein rock

Serpentinite (antigorite/lizardite) with milky quartz; possible chlorite or epidote alteration

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Petrified Wood

Silicified Wood (SiO2)

Quartz Pebble with Chlorite or Epidote Inclusions

Silicon Dioxide (SiO2) with inclusions

Fossil gastropod shell

Fossilized gastropod; likely a spiral marine snail, taxonomic identification uncertain from the image

Petrified Coral (Agatized Coral)

Fossilized Anthozoa (Silicon Dioxide replacement - SiO2)

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Fossil bivalve or brachiopod in sedimentary rock

Unidentified fossil shell impression; likely a ribbed bivalve or brachiopod preserved in shale/siltstone

Chert (Jasper/Flint Pebble)

Microcrystalline quartz (SiO2)

Brecciated jasper, possibly rainforest jasper or brecciated rhyolite

Brecciated microcrystalline quartz (SiO₂), commonly called jasper; the green portions may contain epidote, chlorite, or iron-bearing silicates, while red-brown areas are typically hematite or other iron oxides

Fossilized Echinoid (Sea Urchin)

Echinoidea (Fossil)

Petrified Wood

Silicified Wood (SiO2)

Fossil Shell (Bivalve)

Phylum Mollusca, Class Bivalvia

Green Jasper

Silicon Dioxide (SiO2) with impurities

Fossil bivalve shell

Fossilized marine bivalve; exact genus/species indeterminate from the photograph

Polished yellow jasper or opaque chalcedony bead

Microcrystalline quartz (SiO₂), likely iron-oxide-stained jasper