Limestone (specifically Fossiliferous or Crinoidal Limestone)
Calcium Carbonate (CaCO3) - Calcite Rock
Category
Browse organic gemstone specimens identified by the Rock Identifier community.
Limestone (specifically Fossiliferous or Crinoidal Limestone)
Calcium Carbonate (CaCO3) - Calcite Rock
Limonite-stained Chert
Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)
Chert (Septarian or Nodular variety)
Microcrystalline Quartz (SiO2)
Chert (Common Opal/Jasper variety)
Microcrystalline Quartz (SiO2) with hydration
Petrified Wood
Silicified Wood (SiO2)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Pink Chert (Brecciated Jasmine/Jasper)
Silicon Dioxide (SiO2)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Chert (Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Chert (variations include Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (Quartz, SiO2)
Citrine
Silicon Dioxide (SiO2)
Garnet (Almandine)
Almandine Fe3Al2(SiO4)3
Almandine Garnet in Matrix
Almandine, Fe3Al2(SiO4)3
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
Jasper
Silicon dioxide (SiO2) with iron inclusions
Cat's Eye Moonstone (Feldspar)
Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8) inclusions
Chert (variant Flint/Jasper)
Microcrystalline Opaline Silica (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Green Quartz (Prasiolite)
Crystalline Silicon Dioxide (SiO2)
Rhodochrosite (Beads) and Citrine (Pendant)
Rhodochrosite (MnCO3) and Quartz variety Citrine (SiO2)
Sunstone
(Ca,Na)((Al,Si)2Si2)O8 (Plagioclase Feldspar)
Ambergris (Geological/Organic Specimen)
Ambra grisea (Produced by Physeter macrocephalus)
Faceted Clear Gemstone (Likely Quartz or Cubic Zirconia)
Silicon Dioxide (SiO2) or Zirconium Dioxide (ZrO2)
Blue Topaz
Al2SiO4(F,OH)2 (Aluminum silicate fluoride hydroxide)
Aquamarine
Beryl (Be3Al2Si6O18)
Multi-Gemstone Quartz Bracelet (Amethyst, Aventurine, Rose Quartz, Clear Quartz)
Silicon Dioxide (SiO2) mixture
Colorless Gemstone (possibly Diamond or Cubic Zirconia)
C (Diamond) or ZrO2 (Cubic Zirconia)
Emerald in Host Rock
Beryl (Be3Al2Si6O18) containing Chromium and/or Vanadium
Shale
Shale (fine-grained clastic sedimentary rock)
Moonstone
Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8
Rhodonite
Manganese silicate (Mn,Fe,Mg,Ca)SiO3
Pink Opal
Hydrated Silicon Dioxide (SiO2 · nH2O)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Fossiliferous Rock (likely Dinosaur Fossil in Matrix)
Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)
Brown Jasper / Chert Pebbles
Microcrystalline Quartz (SiO2) with iron oxide impurities
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)