Mineral Specimen

Quartz Pebble

Silicon Dioxide (SiO2)

Iron-Stained Quartz Pebble

Quartz (Silicon Dioxide, SiO2) with Iron Oxide Inclusion/Staining

Beach Pebble (Basalt / Greywacke)

Basalt (or fine-grained Sedimentary Greywacke)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Celestine (or Celestite)

Strontium sulfate (SrSO4)

Gneiss (Metamorphic Rock)

Gneiss

Rutilated quartz crystal

Quartz, silicon dioxide (SiO₂), containing rutile inclusions (TiO₂)

Sandstone

Arenite (Sedimentary Rock)

Sandstone (Quartzose)

Arenite (SiO2 based)

Epidote

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

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartz pebble

Silicon dioxide (SiO2)

Granite

Granite (phaneritic felsic intrusive rock)

Amethyst or Smoky Quartz Geode Slice

Crystalline Silicon Dioxide (SiO2) with iron impurities

White Salt Crystal Lamp (Halite)

Halite (Sodium Chloride, NaCl)

Weathered granite (likely biotite granite)

Granite; interlocking quartz, feldspar, and mica, commonly with biotite

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica (exact identification uncertain from the photo)

Clear Quartz Crystal (Herkimer Diamond style)

Silicon Dioxide (SiO2)

Agate

Chalcedony (SiO2) with impurities

Quartz Geode

Silicon Dioxide (SiO2) within a secondary sedimentary structure

Yellow Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Quartz Geode Cluster (Iron-stained Quartz)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Snowflake Obsidian

Obsidian with Cristobalite inclusions

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Quartz Vein in Hematitic Siltstone

Hydrothermal Quartz (SiO2) in Ferriferous Matrix

Banded gneiss pebble

Gneiss, chiefly quartz–feldspar–mica with dark biotite/amphibole bands

Banded Chert in Matrix

Microcrystalline Quartz (SiO2)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Labradorite (Raw)

(Ca, Na)(Al, Si)4O8

Jasper (likely Brecciated or Multi-colored)

Jasper (SiO2)

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2)

Geode

Silicon Dioxide (Quartz/Chalcedony) in carbonate or volcanic host rock

Leopard Skin Jasper

Silicon Dioxide (SiO2) with impurities

Sandstone

Arenite (principally SiO2)

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grains are fused

Honey calcite (likely)

Calcite — calcium carbonate, CaCO₃

Limonite Concretion

Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O

Feldspar (likely Orthoclase or Plagioclase)

Tectosilicate Feldspar (KAlSi3O8 to (Ca,Na)(Al,Si)4O8)

Argetine Blue Agate (Chalcendony variant)

Silicon Dioxide (SiO₂)