Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Category
Browse metamorphic or igneous specimens identified by the Rock Identifier community.
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Epidote
Epidote; Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.
As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.
Mica Group Minerals
There isn't a single scientific name as 'Mica' refers to a group of phyllosilicate minerals. Common scientific names include Muscovite (KAl₂ (AlSi₃O₁₀)(OH)₂), Biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH)₂), Phlogopite (KMg₃AlSi₃O₁₀(OH)₂), and Lepidolite (K(Li,Al)₃(Al,Si,Rb)₄O₁₀(F,OH)₂).
Yellow Quartz (Citrine/Yellow Chalcedony)
Silicon Dioxide (SiO2)
Lapis Lazuli
Na6Ca2(Al6Si6O24)(S,SO4,Cl)1-2 (primarily containing Lazurite with inclusions of Calcite and Pyrite)
Granodiorite (Gneissic texture)
Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)
Schist
Schist
Gneiss
Gneiss (High-grade regional metamorphic rock)
Foliated Gneiss (River-Worn Pebble)
Gneiss (High-grade Regional Metamorphic Rock)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Lapis Lazuli (Lazurite crystals on Marble)
Lazurite / (Na,Ca)8[(S,Cl,SO4,OH)2|(AlSiO4)6]
Gneiss (Metamorphic Rock)
Gneiss
Hematite (Iron Ore)
Hematite (Fe2O3)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Smoky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz (Milky or Druzy Quartz)
Silicon Dioxide (SiO2)
Amber and Citrine Quartz
Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)
Quartz (Milky or White Quartz)
Silicon Dioxide (SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Pink Tumbled Quartz (Dyed)
Silicon Dioxide (SiO2)
Quartz / Clear Quartz
Silicon Dioxide (SiO2)
Sunstone
Oligoclase or Andesine (Labradorite) Feldspar (Na,Ca)(Si,Al)4O8
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Rough Star Sapphire (Corundum)
Al2O3 (Aluminum Oxide)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
General Gravel (River Rock/River Stones)
Mixed Lithic Sediments (Conglomerate Clasts)
Pink Sapphire
Corundum (Al2O3 with Chromium/Titanium/Iron traces)
Amazonite
Potassium Feldspar (KAlSi3O8)
Moonstone
Adularia (Potassium Aluminum Silicate, KAlSi3O8)
Quartz (Clear/White)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Blue Calcite
Calcium Carbonate (CaCO3)
Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
Quartz (Milky/Yellowish)
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Smoky Quartz
Silicon Dioxide (SiO2)
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
Bull Quartz (White Quartz)
Silicon Dioxide (SiO2)