Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt or Porphyritic Andesite
igneous
Category
Basalt
Browse basalt specimens identified by the Rock Identifier community.
Learn about Basalt in the encyclopedia
View all →
Eclogite
Eclogite (composed primarily of Omphacite and Pyrope Garnet)
metamorphic
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Epidote with Quartz
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
metamorphic
Sunstone
(Ca,Na)(Al,Si)4O8 (Oligoclase or Andesine)
mineral
Greenstone (Epidosite)
Epidosite (Metamorphosed Basalt/Diabase)
metamorphic
Olivine (Peridot)
Magnesium Iron Silicate (Mg, Fe)2SiO4
Mineral
Vesicular Basalt (River Pebble)
Basalt (Mafic volcanic rock)
igneous
Sunstone (Feldspar)
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
mineral
Olivine in Basalt matrix
Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)
igneous
Geode or Concretion
Silica-rich Concretion or Unopened Geode (SiO2)
sedimentary
Chalcedony on Matrix
Silicon Dioxide (SiO2)
mineral
Sparkling Druzy Quartz on Matrix
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Grey Chalcedony
Silicon Dioxide (SiO2)
mineral
Andesite
Andesite (Intermediate Volcanic Rock)
igneous
Amethyst (Raw Cluster)
Silicon Dioxide with iron impurities (SiO2)
mineral
Amygdaloidal Basalt
Vesicular Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)
igneous
Olivine (Peridotite)
(Mg, Fe)2SiO4 (Magnesium Iron Silicate)
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (extrusive volcanic rock with mineral inclusions)
igneous
Basalt River Stone with Quartz Vein
Basalt (Mafic volcanic rock)
igneous
Basalt River Pebble
Basalt (Mafic volcanic rock)
igneous
Carnelian Agate
Chalcedony (SiO2) with iron oxide inclusions
mineral
Sandstone with Iron Banding
Arenite with Hematite or Limonite staining (SiO2 with Fe2O3)
sedimentary
Amethyst
SiO2 (Silicon Dioxide with iron impurities and irradiation)
mineral
Larimar
Blue Pectolite (NaCa2Si3O8(OH))
mineral
Black Onyx
Cryptocrystalline Quartz (SiO2 with organic/iron impurities)
mineral
River Rocks (Basalt and Sedimentary Stones)
Mafic Igneous Rock (Basalt) and Clastic Sedimentary Rock
igneous and sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Chert (Jasper/Chalcedony variety)
Silicon Dioxide (SiO2)
sedimentary
Amygdaloidal Basalt
Basalt with secondary mineral infilling
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Extrusive)
igneous
Porphyritic Basalt
Porphyritic Basalt (with plagioclase phenocrysts)
igneous
Porphyritic Basalt
Porphyritic Basalt (with plagioclase phenocrysts)
igneous
Porphyritic Basalt
Porphyritic Basalt (with Plagioclase phenocrysts)
igneous
Amygdaloidal Basalt
Basalt with Secondary Mineral Infillings
igneous
Gabbro
Gabbro (phaneritic mafic intrusive rock)
Igneous
Diabase (Greenstone)
Diabase (also known as Dolerite)
igneous
Andesite
Andesite (Intermediate Volcanic Rock)
igneous
Diabase (Greenstone)
Diabase or Dolerite
igneous
Banded Agate (Orca Agate)
Silicon Dioxide (SiO2) - Chalcedony variety
mineral
Porphyritic Andesite
Andesite (with white Plagioclase phenocrysts)
igneous