Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Category
Browse mineral like byproduct specimens identified by the Rock Identifier community.
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Sandstone
Arenite (primarily SiO2)
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Limonite (Ironstone)
Hydrated Iron Oxide (FeO(OH)·nH2O)
Nickel
Nickel (Ni)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within a metamorphic matrix
Bauxite
Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Petrified Wood
Silicified wood (primarily SiO2)
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Schist with Quartz/Mica
Mica Schist (primarily Muscovite and Quartz)
Celadonite in Basalt (Green Earth)
Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Druzy Quartz Geode (Oco or Moroccan variety)
Silicon Dioxide (SiO2)
Eclogite
Eclogite (Omphacite + Pyrope)
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Limonite Concretion (Ironstone)
Limonite / Goethite (FeO(OH)·nH2O)
Greenstone
Metamorphosed Mafic Igneous Rock
Sparkling Druzy Quartz on Matrix
Silicon Dioxide (SiO2) with iron oxide inclusions
Banded Onyx (Mexican Onyx / Travertine)
Calcite (CaCO3) - Banded Travertine
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Agate Geode Node
Cryptocrystalline Quartz (SiO2)
Halite
Sodium Chloride (NaCl)
Amygdaloidal Basalt
Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)
Greenstone (Epidote/Chlorite Rich Rock)
Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))
Bornite (Peacock Ore)
Bornite (Cu5FeS4)
Fluorite
Calcium Fluoride (CaF2)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Quartz (possibly Citrine or Smoky Quartz variety)
Silicon Dioxide (SiO2)
Goethite/Limonite Iron Ore Node
Goethite (FeO(OH)) or Limonite (mixture of hydrated iron oxides)
Fluorite
Calcium Fluoride (CaF2)
Dendritic Quartz Pebble
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
Amygdaloidal Basalt
Basalt with Secondary Mineral Infillings
Sandstone (Yellow/Siltstone variant)
Arenite (SiO2 primarily)
Sandstone
Arenite (primarily composed of SiO2)
Bauxite
Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)
Quartz Geode
Silicon Dioxide (SiO2)