Petrified Wood
Silicified Wood (SiO2 / Quartz pseudomorph after wood)
fossil
Category
Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material) in the encyclopedia
View all →
Raw Agate (Rough Lake Superior Agate or Jasper-Chalcedony Nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
mineral
Greenish Feldspathic Rock / Epidote Granite (Unakite-type or Epidote-bearing rock)
Epidotized Metamorphic/Igneous Rock
metamorphic
Precious Opal in Matrix
Hydrated Silica (SiO2·nH2O)
mineral
Fossiliferous Limestone (Coquina)
Calcite (CaCO3) with Bioclastic inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Fossilized Shark Tooth
Elasmobranchii gen. sp. indet. (Calcium Phosphate - Ca5(PO4)3(OH,F,Cl))
fossil
Chert (Brecciated or Veined)
Silicon Dioxide (SiO2)
sedimentary
Amber
Fossilized Tree Resin (C10H16O)
gemstone
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Quartz (Quartz Pebble)
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)
mineral
Pink Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Granite
Phaneritic Igneous Rock (Granite)
igneous
Quartz (Druzy or Crystalline variety)
Silicon Dioxide (SiO2)
mineral
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
mineral
Hag Stone
Perforated Quartz Pebble / Sedimentary Rock
sedimentary
Iron-rich breccia (hematite–goethite rock)
Hematite (Fe₂O₃) and goethite (FeO(OH)) ironstone, likely ferruginous breccia
sedimentary
Fossilized Shark Tooth
Carcharhinus sp. (likely Bull or Requiem shark family)
sedimentary
Blue-gray metamorphic rock, likely gneiss or schist
Quartz–feldspar–mica assemblage; exact identification requires testing
metamorphic
Petrified Wood
Silicified wood (primarily SiO2)
fossil
Blue Apatite
Apatite group (Ca5(PO4)3(F,Cl,OH))
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Quartz Vein in Hematitic Siltstone
Hydrothermal Quartz (SiO2) in Ferriferous Matrix
metamorphic
Shale
Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Greenstone (likely altered basalt or serpentinite)
Chlorite-rich metabasalt or serpentinite; exact identification requires testing
metamorphic
Mammoth or Mastodon Tooth Fragment
Mammuthus / Mammut molar fragment
fossil
Jasper
Silicon dioxide (Quartz variety), SiO2
sedimentary
Red Jasper (Polished)
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
sedimentary
Quartz (likely Rose Quartz or Milky Quartz based on color)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Mineraloid
Shungite
Non-crystalline carbon (allotrope of carbon)
metamorphic
Green Opal (Prase Opal)
SiO2 · nH2O (Hydrated Silicon Dioxide)
mineral
Diamond (Cut Specimen)
Diamond (pure carbon, C)
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Schist
Mica Schist
metamorphic
Red Jasper
Silicon dioxide (SiO2) with iron oxide (Fe2O3) inclusions
sedimentary/mineral