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Emerald in Matrix

Emerald (Beryllium Aluminum Silicate), Be3Al2(SiO3)6

Chalcedony (Botryoidal or Geode form)

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Biogenic Calcium Carbonate (CaCO3)

Chert Pebble

Microcrystalline Quartz (SiO2)

Banded Agate (Tumbled)

Silicon Dioxide (SiO2) - variety of Chalcedony

Quartz Geode

Silicon Dioxide (SiO2)

Banded Agate

Agate (Cryptocrystalline variety of Silica, SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Banded Sandstone (Liesegang Rings)

Sedimentary sandstone with Iron oxide precipitates

Fluorite

Calcium Fluoride (CaF2)

Included Quartz Beads (likely Phantom Quartz or Garden Quartz)

Quartz (SiO2) with various mineral inclusions

Amethyst (Druze)

Silicon Dioxide (SiO2) with iron impurities

Diorite

Diorite (Intermediate Plutonic Rock)

Amethyst (Geode/Druzy)

Silicon Dioxide (SiO2) with iron impurities

Pyrite (on Quartz matrix)

Iron Sulfide (FeS2)

Limonite (Iron Ore)

Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Agate (specifically a Thunderegg/Agate Nodule)

Cryptocrystalline Quartz (SiO2)

Sandstone (Quartzite-rich Cobble)

Clastic sedimentary rock (primarily SiO2)

White Agate (Tumbled)

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Titanium Coated Kyanite (Aura Kyanite)

Aluminosilicate (Al2SiO5) with a Titanium-Niobium vacuum-deposited coating

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Volcanic Rock)

Diopside (likely Chromian Diopside)

Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.

Chert (often called Flint or River Stone)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Chalcopyrite

Chalcopyrite (CuFeS2)

Quartz-veined Mudstone or Argillite

SiO2 (Quartz) in Siltstone/Mudstone matrix

Zebra Jasper

Silicon Dioxide (SiO2) - Macro-crystalline Quartz/Chert with impurities

Diamond

Diamond (pure carbon, C)

Red Tiger's Eye

Silicified Crocidolite (Quartz pseudo-morph after Crocidolite), SiO2

Gold Nugget

Native Gold (Au)

Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Amethyst

Amethyst (variety of Quartz, SiO2)

Silicon Carbide (Carborundum)

Silicon Carbide (SiC)

Conglomerate (River Rock Aggregate)

Conglomerate (Lithic-clast conglomerate)

Chert (specifically Jasper or Brown Chert node)

Microcrystalline Quartz (SiO2)

Yellow Chalcedony or River Jasper

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Rhodonite

Rhodonite (MnSiO3)

Andesite Porphyry

Andesite (Intermediate Volcanic Rock)

Amethyst Quartz Druse

Silicon Dioxide (SiO2) with iron impurities

Basalt with Garnet inclusions

Basalt containing Nesosilicate (Garnet Group, likely Almandine Fe3Al2Si3O12)