Ammonite Fossil in Matrix
Ammonoidea subclass (e.g., Arietites or similar genera)
fossil
Category
Mineral (Synthetic Paper And Ink Polymorph)
Browse mineral (synthetic paper and ink polymorph) specimens identified by the Rock Identifier community.
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Sandstone (Water-worn Cobble)
Arenite (variable composition, primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Polished septarian nodule
Calcite–aragonite–barite septarian concretion, commonly in a claystone or limestone matrix
sedimentary
Diamond (or Cubic Zirconia)
Cubic Carbon (C) or Zirconium Dioxide (ZrO2)
gemstone
Opalite
Synthetic Glass (Amorphized Silicon Dioxide)
mineraloid
Polished agate/jasper nodule
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide impurities
mineral
Agate Geode Node
Cryptocrystalline Quartz (SiO2)
mineral
Dyed Purple Agate
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Graphite Schist
C (Carbonaceous Schist)
metamorphic
Quartz River Cobble
Silicon Dioxide (SiO2)
Mineral (Primary constituent)
Polished Septarian Nodule
Septarian calcite–aragonite concretion, commonly with barite or celestine
sedimentary
Agate Sliced Nodule
Silicon Dioxide (SiO2)
mineral
Tumbled brown agate
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions
mineral
Agate Slice (Carnelian Agate)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Dyed Agate Geode Slice
Silicon Dioxide (SiO2) - Banded Chalcedony
mineral
Septarian Nodule
Septarian concretion (composition: Calcium carbonate, Aragonite, and Siderite/Baryte)
sedimentary
Thunderegg (specifically a Jasper/Agate-filled Geode nodule)
Silicon Dioxide (SiO2) within Rhyolitic Matrix
igneous
Kyanite in Quartz
Kyanite (Al2SiO5) with Quartz (SiO2) matrix
metamorphic
Fossilized Coral (Petoskey-like or Favosites)
Anthozoa (Fossilized Coral)
sedimentary
Tumbled banded metamorphic stone
Likely banded gneiss or migmatitic gneiss; exact identification requires testing
metamorphic
Inspirational River Stone (Quartzite)
Metamorphosed Quartz-rich Rock (Quartzite) with SiO2 composition
metamorphic
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)
sedimentary
Opaline Glass (Opalite)
Synthetic Silicon Dioxide Glass
Mineraloid (Man-made)
Septarian Nodule (Micro-fragment)
Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)
sedimentary
Polished/tumbled septarian nodule (likely)
Calcite–aragonite–barite septarian concretion; composition varies, commonly calcite (CaCO₃) with clay/mudstone and iron oxides
sedimentary
Polished banded agate (likely sardonyx)
Cryptocrystalline chalcedony, SiO₂; reddish bands are iron-stained layers
mineral
Banded Agate (specifically Sardonyx or Carnelian Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Amber
Succinite
Mineraloid
Banded Agate (Dyed Purple)
Agate (Variety of Chalcedony/Quartz), SiO2
mineral
Tumbled jasper, likely picture or brecciated jasper
Microcrystalline quartz (SiO₂) with iron-oxide and other mineral impurities
gemstone
Yellow Banded Agate
Silicon Dioxide (SiO₂)
mineral
Petoskey Stone
Hexagonaria percarinata
fossil
Granite Cobble
Granite
igneous
Polished brecciated jasper (likely septarian or iron-rich jasper)
Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments
sedimentary
Septarian Nodule
Septarian concretion (Complex mixture of Siderite, Calcite, and Aragonite)
sedimentary
Clear Quartz (Facet Cut / Polished)
Silicon Dioxide (SiO2)
mineral
Fossil Coral (Petoskey Stone / Rugose Coral)
Hexagonaria percarinata (or similar fossilized rugose/tabulate coral)
fossil
Quartz-veined Limestone
Sedimentary limestone with hydrothermal quartz/calcite veins (CaCO3 / SiO2)
sedimentary
Faceted Quartz or Cubic Zirconia
SiO2 (Quartz) or ZrO2 (Cubic Zirconia)
gemstone
Banded Agate (specifically Carnelian Agate)
Silicon Dioxide (SiO2)
mineral
Tumbled agate/chalcedony
Microcrystalline quartz (SiO₂), likely agate or jasper-bearing chalcedony
mineral