Rock Identifier

Category

Mineraloid (Cryptocrystalline Quartz)

Browse mineraloid (cryptocrystalline quartz) specimens identified by the Rock Identifier community.

Red Jasper (Jasper (a variety of Chalcedony, SiO₂)) — Mineraloid (cryptocrystalline quartz)

Red Jasper

Jasper (a variety of Chalcedony, SiO₂)

Mineraloid (cryptocrystalline quartz)

Snowflake Obsidian (Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

Obsidian (Volcanic glass (mainly SiO2 with inclusions)) — igneous

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

Limonite/Goethite on Shale (Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock) — sedimentary

Limonite/Goethite on Shale

Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock

Limonite (Iron Ore) (Hydrous ferric oxides (FeO(OH)·nH2O)) — mineral

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

Snowflake Obsidian (Flower Jasper variant) (Vitreous volcanic silicate with cristobalite inclusions) — igneous

Snowflake Obsidian (Flower Jasper variant)

Vitreous volcanic silicate with cristobalite inclusions

Snowflake Obsidian (Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)

Snowflake Obsidian (Volcanic Glass with Cristobalite inclusions (70–75% SiO2)) — Igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions (70–75% SiO2)

Common Opal in Host Rock (Hydrated Silica (SiO2·nH2O)) — mineraloid

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Pink Opal (Hydrated Amorphous Silica (SiO2·nH2O)) — mineraloid

Pink Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Green Opal (Hydrated Silica (SiO2·nH2O)) — mineraloid

Green Opal

Hydrated Silica (SiO2·nH2O)

Ethiopian Opal (Welo Opal) (Hydrated Amorphous Silica (SiO2·nH2O)) — mineraloid

Ethiopian Opal (Welo Opal)

Hydrated Amorphous Silica (SiO2·nH2O)

Amber (Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)) — Mineraloid

Amber

Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)

Snowflake Obsidian (Volcanic glass with Cristobalite inclusions (mostly SiO2)) — igneous

Snowflake Obsidian

Volcanic glass with Cristobalite inclusions (mostly SiO2)

Limonite and Goethite (Ironstone) (Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)) — sedimentary

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Snowflake Obsidian (Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)

Snowflake Obsidian (Spherulitic Volcanic Glass (SiO2 + impurities)) — igneous

Snowflake Obsidian

Spherulitic Volcanic Glass (SiO2 + impurities)

Sea Glass (Frosted Quartz/Glass) (Amorphous Silicon Dioxide (SiO2)) — Mineraloid

Sea Glass (Frosted Quartz/Glass)

Amorphous Silicon Dioxide (SiO2)

Limonite with Quartz (Gossan) (Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)) — Mineral

Limonite with Quartz (Gossan)

Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)

Chalcedony (or a variety of Chalcedony, likely Agate or Jasper) (Chalcedony (SiO₂)) — Mineral (or mineraloid if microcrystalline)

Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)

Chalcedony (SiO₂)

Mineral (or mineraloid if microcrystalline)

Mahogany Obsidian (Volcanic glass (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic glass (SiO2 + Fe2O3)

Limonite (Iron Ore) (Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)) — Mineral

Limonite (Iron Ore)

Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)

White Opal (Common) (Hydrated Silica (SiO2·nH2O)) — mineral

White Opal (Common)

Hydrated Silica (SiO2·nH2O)

Black Obsidian (Volcanic Glass (predominantly SiO2, Silicon Dioxide)) — igneous

Black Obsidian

Volcanic Glass (predominantly SiO2, Silicon Dioxide)

Carnelian (Carnelian (SiO2)) — mineral

Carnelian

Carnelian (SiO2)

Agate Geode (Cryptocrystalline Quartz (SiO2)) — mineral

Agate Geode

Cryptocrystalline Quartz (SiO2)

Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles (Mixed gemstones (primarily Silicon Dioxide - SiO2)) — mineral

Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles

Mixed gemstones (primarily Silicon Dioxide - SiO2)

Jasper (yellow/cream variety) (SiO₂ (Cryptocrystalline Quartz)) — Sedimentary

Jasper (yellow/cream variety)

SiO₂ (Cryptocrystalline Quartz)

Carnelian and White Quartz Bracelet (Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz) — mineral

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Chalcedony (Cryptocrystalline Quartz (SiO2)) — mineral

Chalcedony

Cryptocrystalline Quartz (SiO2)

Onyx (Chalcedony (SiO2) with parallel banding) — mineral

Onyx

Chalcedony (SiO2) with parallel banding

Quartz (likely a form of massive or vein quartz) (Quartz (SiO₂)) — Mineral

Quartz (likely a form of massive or vein quartz)

Quartz (SiO₂)

Red Sandstone (Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)) — sedimentary

Red Sandstone

Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)

Chert Breccia (Brecciated Chert (Microcrystalline Silica)) — sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

Gray Agate with Druzy Quartz Geode (Cryptocrystalline Quartz (SiO2)) — mineral

Gray Agate with Druzy Quartz Geode

Cryptocrystalline Quartz (SiO2)

Banded Agate (Carnelian variety) (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate (Carnelian variety)

Cryptocrystalline Quartz (SiO2)

Banded Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

Chert (Common Opal/Jasper variety) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Common Opal/Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chalcedony (Cryptocrystalline Quartz (SiO2)) — mineral

Chalcedony

Cryptocrystalline Quartz (SiO2)

Chert (specifically Brown Chert or Flint) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Brown Chert or Flint)

Cryptocrystalline Quartz (SiO2)

Chert (varietal: Flint/River Pebble) (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (varietal: Flint/River Pebble)

Cryptocrystalline Quartz (SiO2)

Banded Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)