Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Category
Metamorphic Or Igneous (Context Dependent)
Browse metamorphic or igneous (context dependent) specimens identified by the Rock Identifier community.
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
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.
Mineral, possibly rock fragment containing a mineral
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).
Mineral
Yellow Quartz (Citrine/Yellow Chalcedony)
Silicon Dioxide (SiO2)
mineral
Granodiorite (Gneissic texture)
Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)
igneous
Schist
Schist
metamorphic
Ferruginous Quartz (Iron-stained Quartz)
Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)
mineral
Gneiss
Gneiss (High-grade regional metamorphic rock)
Metamorphic
Foliated Gneiss (River-Worn Pebble)
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Gneiss (Metamorphic Rock)
Gneiss
metamorphic
Hematite (Iron Ore)
Hematite (Fe2O3)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Smoky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Quartz (Milky or Druzy Quartz)
Silicon Dioxide (SiO2)
mineral
Amber and Citrine Quartz
Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)
mineral
Quartz (Milky or White Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Pink Tumbled Quartz (Dyed)
Silicon Dioxide (SiO2)
mineral
Quartz / Clear Quartz
Silicon Dioxide (SiO2)
mineral
Sunstone
Oligoclase or Andesine (Labradorite) Feldspar (Na,Ca)(Si,Al)4O8
mineral
Quartz (River Pebble)
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Rough Star Sapphire (Corundum)
Al2O3 (Aluminum Oxide)
mineral
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
mineral
General Gravel (River Rock/River Stones)
Mixed Lithic Sediments (Conglomerate Clasts)
sedimentary
Pink Sapphire
Corundum (Al2O3 with Chromium/Titanium/Iron traces)
mineral
Amazonite
Potassium Feldspar (KAlSi3O8)
mineral
Moonstone
Adularia (Potassium Aluminum Silicate, KAlSi3O8)
mineral
Quartz (Clear/White)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
Mineral
Smoky Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Quartz (Milky/Yellowish)
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
mineral
Bull Quartz (White Quartz)
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Smoky Quartz (SiO2)
mineral
Banded Chalcedony (Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Moonstone
Orthoclase Feldspar (KAlSi3O8) or Albite mixtures
mineral