Devil's Toenail
Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)
Category
Browse organic gemstone (fossilized resin) specimens identified by the Rock Identifier community.
Devil's Toenail
Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Chert (often called Jasper or Flint)
Microcrystalline Silica (SiO2)
Petrified Wood
Silicified wood (principally SiO2)
Jasper (Red Jasper)
Silicon Dioxide (SiO₂)
Fossilized Crinoid Stem
Crinoidea (Echinodermata)
Cannonball Concretion
Calcite-cemented Sandstone Concretion
Sandstone
Arenite (SiO2 based)
Crinoid Stem Fossil in Matrix
Phylum Echinodermata, Class Crinoidea
Petoskey Stone
Hexagonaria percarinata
Sandstone
Arenite (SiO2 with various cementation agents)
Dendritic Rhodonite
Rhodonite (Manganese Silicate), (Mn,Fe,Mg,Ca)SiO3
Sandstone with Dendritic Manganese Oxides
Sandstone (SiO2 predominant) with Oxide Dendrites (MnO2)
Septarian Nodule
Septarian Concretion (Composition: Calcite, Aragonite, and Limestone/Clay)
Orbicular Jasper (Eye Jasper / Kambaba-like pattern)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Tree Agate
Silicon Dioxide (SiO2) - Dendritic Agate/Chalcedony
Sandstone Concretion
Sandstone (Sedimentary Rock) with silica or calcite cement
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Banded Agate (Dyed)
SiO2 (Silicon Dioxide / Microcrystalline Quartz)
Chert (River Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Polished ocean jasper (orbicular jasper), likely
Silica-rich microcrystalline quartz/chalcedony aggregate, commonly with feldspar, epidote, and iron oxides; composition varies
Orange calcite fragment
Calcite (CaCO₃), likely iron-stained or orange-colored calcite
Jasper
Silicon Dioxide (SiO2)
Pearl
Organic Mineral (CaCO3 with conchiolin)
Moss Agate
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
Petoskey Stone (Fossilized Coral)
Hexagonaria percarinata
Chert (Flint Pebbles)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Chert (SiO2)
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
Petoskey Stone
Hexagonaria percarinata
Siderite Concretion (Nodule)
Iron Carbonate (FeCO3) Concretion
Limestone
Calcium Carbonate (CaCO3)
Chert (often called Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert
Chert (Microcrystalline Quartz, SiO2)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Precious Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Chert (Smooth River Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Fossilized Coral (Petrified Coral)
Anthozoa fossil
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Petoskey Stone (Fossilized Rugose Coral)
Hexagonaria percarinata