Igneous And Sedimentary

Heliotrope (Bloodstone)

Cryptocrystalline Quartz (SiO2) with inclusions of Hematite (Fe2O3)

Gneiss

Gneiss

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss (Banded Gneiss)

Gneiss

Chalcedony (Smoky Quartz or Agate nodule fragment)

Silicon Dioxide (SiO2)

Chalcedony (Agate/Carnelian precursor)

Chalcedony (Silicon Dioxide, SiO2)

Specular Hematite

Hematite (Fe2O3)

Epidote

Epidote; Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

Druzy Quartz (part of a Geode)

Silicon Dioxide (SiO2)

Epidote with Magnetite/Hematite inclusions

Epidote (Ca2(Al2,Fe3+)(SiO4)3(OH)) with Iron Oxides

Gneiss

High-grade regional metamorphic rock (Foliated)

Chalcedony with inclusions (Agate/Quartz)

Silicon Dioxide (SiO2)

Biotite Gneiss

Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Nuummite

Nuummite (Orthoamphibole rock / Anthophyllite-Gedrite blend)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Grey River Stone (Gneiss/Schist mix)

Foliated Metamorphic Rock (variable mineral formula)

Botryoidal Agate / Chalcedony Geode

Silicon Dioxide (SiO2)

Common Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Gneiss

Gneiss

Gneiss (specifically a water-worn pebble)

Gneiss

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

Gneiss

High-grade metamorphic rock (Gneiss)

Quartz (Druzy/Macro-crystalline)

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Quartz / Quartz Geode fragment

Silicon Dioxide (SiO2)

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Botryoidal Chalcedony (Agate/Desert Rose Chalcedony)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Gneiss (with Quartzite and Biotite)

Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss

Gneiss

Quartz Druzy (on Calcedony/Quartz base)

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Banded Gneiss (with Quartz Vein)

Gneiss (Metamorphic rock of varying mineralogy)

Gneiss

Gneiss (High-grade metamorphic rock)

Quartz Geode

Silicon dioxide (SiO2)

Gneiss (specifically Banded Gneiss)

Gneiss

Banded Gneiss

Gneiss (Metamorphic high-grade, predominantly SiO2, Al2O3, K2O, Na2O)

Gneiss (specifically Micaceous Gneiss)

Gneiss (High-grade Regional Metamorphic Rock)

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss (with Mica and Quartz)

Gneissic Metamorphic Rock

Gneiss

Gneiss