Petrified Wood
Silicified Wood (SiO2)
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
Agatized Fossil (Druzy Agate)
Silicon Dioxide (SiO2) replacing organic matter
Petrified Wood
Fossilized Wood (silicified wood)
Chert (Arrowhead Artifact)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Blue Apatite
Calcium Phosphate (Ca5(PO4)3(F,Cl,OH))
Limestone
Calcium Carbonate (CaCO3)
Jasper
Microcrystalline Quartz (SiO2)
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Blue Apatite
Apatite, Ca5(PO4)3(F,Cl,OH)
Travertine (used in construction, not a 'specimen' in situ)
Travertine
Green Jasper
Silicon Dioxide (SiO2)
Desert Rose (Baryte or Selenite variant)
Barium Sulfate (BaSO4) or Gypsum (CaSO4·2H2O) with Sand inclusions
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Graphite
Graphite (Carbon, C)
Quartz Geode
Silicon Dioxide (SiO2)
Chert Nodule
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Chert (and Chalcedony)
Silicon Dioxide (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Red Jasper with Fossils
Silicified Fossiliferous Jasper (Chert variant, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Banded Gneiss / Veined Metamorphic Pebble
Metamorphic Rock with Quartz/Feldspar Veins
Fossilized Coral in Chert
Anthozoa (Class) fossil in Cryptocrystalline Quartz (SiO2)
Amber
Succinite (fossilized resin, C10H16O)
Black Jasper
Silicon Dioxide (SiO2) with inclusions
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Petrified Wood
Silicified Wood (SiO2)
Amber
Succinite / Fossilized Resin (C10H16O)
Blue Apatite
Apatite - Ca5(PO4)3(F,Cl,OH)
Petrified Wood
Silicified Wood (SiO2)
Chert with Quartz Vein
Microcrystalline Quartz (SiO2)
Fossil Shark Tooth
Elasmobranchii tooth fossil (e.g., Otodus / Carcharocles)
Petrified Wood
Silicified Wood (SiO2)
Petrified Palmwood
Palmoxylon (fossilized monocot xylem)
Petrified Wood
Silicified wood (primarily SiO2)
Lemon (Mock specimen mimicking Citrine/Sulfur)
Citrus x limon