Pearl
Biogenic CaCO3 (Aragonite and Calcite)
mineral
Category
Man Made
Browse man made specimens identified by the Rock Identifier community.
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Diamond
Diamond (pure Carbon, C)
mineral
Fossilized Coral (Coquina/Limestone)
Cnidaria Anthozoa (Fossilized)
sedimentary
Diamond
Diamond (pure Carbon, C)
mineral
Faceted transparent gemstone pendant
Uncertain from image; likely faceted quartz (SiO₂), cubic zirconia (ZrO₂), or glass imitation
gemstone
Engineered Quartz (Quartzite look-alike)
Silicon Dioxide (SiO2) composite
mineral-based composite
Diamond (or Cubic Zirconia)
Carbon (C) or Zirconium Dioxide (ZrO2)
gemstone
Coquina
Biogenic Limestone (Coquina)
sedimentary
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Lava Rock (Dyed)
Basalt / Volcanic scoria
igneous
Fossilized echinoid (sea urchin), likely a flint/chalk-associated test
Echinoid fossil; likely a regular echinoid such as Echinocidaris or related taxon, composed mainly of recrystallized calcite (CaCO₃)
fossil
Diabase (Dolerite)
Diabase / Dolerite
igneous
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
igneous
Tumbled chalcedony pendant (likely agate)
Chalcedony, microcrystalline quartz (SiO₂); the pale bands suggest agate
gemstone
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Siltstone Pebble
Siltstone (composed of microscopic quartz and clay minerals)
sedimentary
Quartzite
Metamorphic Quartz Arenite (SiO2)
metamorphic
Chert
Microcrystalline quartz (SiO2)
sedimentary
Quartzite
Metamorphic Quartz Rock (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Arenite (SiO2)
metamorphic
Flint
Silicon Dioxide (SiO2)
sedimentary
Flint (chert)
Microcrystalline quartz (SiO₂), a variety of chert
sedimentary
Red jasper (likely)
Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored red by iron oxides
mineral
Chert (likely flint)
Microcrystalline quartz (SiO₂), variety chert; flint is a dark chert variety
sedimentary
Chert
Sedimentary cryptocrystalline silica (SiO2)
sedimentary
Tumbled yellow-brown chalcedony (likely agate)
Microcrystalline quartz, SiO₂; chalcedony, possibly iron-stained agate
mineral
Brecciated jasper
Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide staining
sedimentary
Chert (White Chert/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled brown chalcedony or agate
Microcrystalline quartz (SiO₂), likely chalcedony; possibly iron-stained jasper or agate
gemstone
Peanut Wood (Fossilized Wood in Radiolarite)
Petrified Wood (Silicified)
fossil
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
mineral
Gypsum (Satin Spar / Alabaster variety)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Chert (Flint / Quartz Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
sedimentary
Chert (variations include Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Granite
Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)
igneous
Goldstone (aventurine glass)
Synthetic copper-bearing soda-lime glass; commonly sold as red goldstone
gemstone
Belemnoit (Fossil)
Belemnoidea (Order), Rostrum / Guard
sedimentary
Clear crystal-bead bracelet, possibly quartz
Unidentified transparent mineral beads; quartz (SiO₂) is one possibility
mineral
Gem-set gold ring
Gold alloy setting with a colorless faceted gemstone, possibly quartz or glass; the stone cannot be identified reliably from the image
gemstone
Faceted clear gemstone ring, likely white sapphire or diamond
Unidentified colorless gemstone; diamond (C) or sapphire (Al₂O₃) cannot be distinguished from the image
gemstone
Fossil or modern bivalve shell
Calcium carbonate shell, likely aragonite (CaCO₃); exact species cannot be determined from the image
fossil