Blue Chalcedony
Silicon Dioxide (SiO2)
mineral
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Dendritic Jasper (Bumblebee like Agate)
Silicon Dioxide with inclusions (SiO2)
sedimentary
Basalt with Quartz Veins
Vesicular or aphanitic Basalt with SiO2 (Quartz) intrusions
Igneous
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Ferruginous Sandstone
Arenite with Hematite/Limonite cement (SiO2 + Fe2O3)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Pink Diamond
Carbon (C)
mineral
Rose Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Citrine Quartz
Silicon Dioxide (SiO2)
mineral
Asphalt Concrete (Bituminous Concrete)
Bituminous aggregate
sedimentary
Pink Tourmaline (Rubellite)
Elbaite (Tourmaline group) - Na(Li,Al)3Al6(BO3)3Si6O18(OH)4
mineral
Green Fluorite
Fluorite (Calcium Fluoride) - CaF2
mineral
Rough Ruby
Corundum (Al2O3 with Chromium impurities)
mineral
Terracotta (Man-made ceramic brick fragment)
Baked clay / High-iron ceramic (Silicate-based ceramic)
Anthropogenic material (Man-made sedimentary mimic)
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
sedimentary
Shattuckite (Blue Quartz/Jasper Matrix)
Shattuckite (Copper Silicate Hydroxide - Cu5(SiO3)4(OH)2)
mineral
Ruby in Fuchsite
Cr-rich Muscovite (Fuchsite) with Corundum (Ruby)
metamorphic
Chert (Tan/Grey variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Diorite
Diorite
igneous
Diabase (also known as Dolerite)
Diabase
igneous
Chrysocolla on Limonite Matrix
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) on FeO(OH)·nH2O (Limonite)
mineral
Greenstone (possibly Basalt or Greenschist)
Greenschist (composed primarily of chlorite, actinolite, and epidote)
Metamorphic (low-grade)
Granite
Phaneritic Plutonic Felsic Rock
igneous
Chert (often called Flint or Jasper based on color)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Bryozoan Fossil
Phylum Bryozoa (commonly known as 'moss animals')
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Rhodonite
Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Sedimentary
Hematite Nodule
Hematite (Fe2O3)
mineral
Chert
Chert (SiO2)
sedimentary
Amazonite
Amazonite (KAlSi3O8); a green variety of Microcline feldspar
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Rose Quartz (tumbled)
Rose Quartz (variety of Quartz, chemical formula SiO₂)
Mineral
Lepidolite on Matrix
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
mineral
Geode (unopened) or Calcareous Nodule
Siliceous or Calcareous Concretion/Nodule
sedimentary
Gabbro
Gabbro (mafic intrusive igneous rock)
igneous
Basalt River Stone
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
igneous
Gold Nugget
Native Gold (Au)
mineral