Black Tourmaline (Schorl)
NaFe3Al6(BO3)3Si6O18(OH)4
Category
Browse mixed specimens identified by the Rock Identifier community.
Black Tourmaline (Schorl)
NaFe3Al6(BO3)3Si6O18(OH)4
River Pebbles (Mixed Lithology)
Conglomerate clasts (Silica-rich and Metamorphic assemblages)
Mixed Mineral and Fossil Collection
Multi-specimen assemblage (SiO2, CaCO3, FeS2, etc.)
Mixed Gemstone Beaded Jewelry
Various minerals (e.g., Quartz varieties like Rose Quartz, Amethyst; Peridot; Garnet; etc.)
Azurite-Malachite (often a mixed specimen)
Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.
Jadeite and Mixed Gemstones (Ruby, Sapphire, Emerald)
Jadeite (NaAlSi2O6), Corundum (Al2O3), Beryl (Be3Al2(Si6O18))
Jasper and Basalt (Mixed Breccia or Chert)
Silicon Dioxide (SiO2) with Ferromagnesian silicates
Mixed Chalcedony and Jasper Bracelet (possibly 'Ocean Jasper' or similar banded variety for brown beads, and blue/grey Chalcedony for the translucent beads)
Chalcedony (SiO2), Jasper (SiO2 with impurities)
Amazonite (likely mixed with other feldspars/minerals)
Amazonite is a variety of Microcline, which is a tectosilicate mineral, formula KAISi3O8. The mixed beads could include other feldspars or quartz.
Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)
Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)
Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)
Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(OH)₄(BO₃)₃Si₆O₁₈)
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Assorted Tumbled Gemstones
Mixed oxides and silicates (including Quartz, Chalcedony, and Feldspar variants)
Silver (Sterling Silver)
Argentum (Ag) mixed with Copper (Cu); Formula: Ag+Cu
Ironstone Pebble
Ferruginous sedimentary rock (Fe2O3 / FeO(OH) mixed with SiO2)
Pumice
Vesicular volcanic glass (Amorphous silica mixed with various oxides)
Bauxite
Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)
Ocean Jasper Mushroom
Orbicular Jasper (Silicon Dioxide, SiO2 mixed with various impurities)
Ironstone Concretion (Moqui Marble)
Iron Oxide Concretion (Fe2O3 / FeO(OH) mixed with SiO2)
River Rock (Glacial Cobbles)
Fluvial Alluvium (Mixed lithology including Quartzite, Basalt, and Granite)
Tiffany Stone
Bertrandite (Be4Si2O7(OH)2) mixed with Fluorite (CaF2), Opal, and Chalcedony
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Black Tourmaline (Schorl)
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Graphite
Graphite (Carbon, C)
Mixed Agate and Lapis Lazuli Bracelet
Chalcedony (SiO2) and Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2
Chakra Stone Bracelet (mixed gemstones)
Multi-mineral/Gemstone assembly (primarily Quartz variety beads)
Fossiliferous Limestone (Chert/Clay mixed)
Calcium Carbonate (CaCO3) / Silicon Dioxide (SiO2)
Aquamarine
Aquamarine (Beryl variety) - Be3Al2(Si6O18)
Mixed Quartz Bracelet (Rose Quartz and Larimar-colored beads)
Silicon Dioxide (SiO2) with various inclusions
Rough Gemstone Grains (Mixed Sapphires and Quartz)
Corundum (Al2O3) and Quartz (SiO2)
Mixed Tumbled Stones (Mostly Agate, Jasper, and Quartz)
Silicon Dioxide (SiO2)
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Yellow Ochre / Limonite
Limonite (inter-mixed iron oxides and hydroxides, primarily FeO(OH)·nH2O)
Rhyolitic Tuff (Breccia Type)
Rhyolitic Pyroclastic Rock (Mixed Silicates including Quartz, Feldspar, and Volcanic Glass)
Black Tourmaline (Schorl)
Schorl (Na(Fe^2+)3Al6(Si6O18)(BO3)3)(OH)3(OH))
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite)
Mookaite Jasper
Siliceous sedimentary rock (variety of Jasper/Chert)
Ironstone Concretion (Limonite/Hematite Nodules)
Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)
Fancy Jasper
Chalcedony (cryptocrystalline quartz) with inclusions
Garnet (likely Almandine, Pyrope, or a blend)
Garnet group minerals: X3Y2(SiO4)3, where X and Y represent various metal ions (e.g., Almandine: Fe3Al2(SiO4)3, Pyrope: Mg3Al2(SiO4)3)
Shale
Shale