Tektite (Natural Glass)

Mixed pebble collection, including likely flint, quartzite, and fossil material

Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil

Picture Jasper

Impure variety of silica (SiO2)

Red jasper pebble

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Black Onyx

Onyx (Silicon Dioxide, SiO2)

Chert (Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Red jasper pebble

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Blue Sapphire

Corundum (Al2O3)

Diamond

Carbon (C)

Polished black stone egg, probably black obsidian

Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements

Polished brecciated jasper

Jasper, opaque microcrystalline quartz (SiO₂), likely brecciated jasper with iron-oxide and dark silicate inclusions

Blue and White Quartz

Crystalline Silicon Dioxide with inclusions (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Slag

Ferrous Slag (Siliceous industrial waste)

Amethyst cluster

Quartz, SiO₂; purple coloration is caused mainly by iron-related defects and natural irradiation

Smoky Quartz on Matrix

Crystalline Silicon Dioxide (SiO2)

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material

Pearl

Calcium carbonate (Aragonite/Calcite) - CaCO3

Green Jasper

Silicon Dioxide (SiO2) with iron silicate inclusions

Tumbled blue-green fluorite (probable)

Fluorite, calcium fluoride (CaF₂)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Black tourmaline beads (likely schorl)

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Smoky quartz

Quartz (SiO₂), brown-to-gray smoky variety

Jasper Chert

Microcrystalline Quartz (SiO2) with iron oxide inclusions

Black Onyx

Silicon Dioxide (SiO2)

Worn quartz-rich pebble, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly quartzite

Quartz-rich vein rock, likely milky quartz in weathered host rock

Milky quartz (SiO₂), probably with weathered feldspar and iron-oxide staining

Tumbled chalcedony or quartz-rich stone

Microcrystalline quartz, SiO₂; possibly pale chert or chalcedony

Carnelian (red chalcedony), possibly red agate or jasper

Chalcedony, a microcrystalline variety of quartz; silicon dioxide (SiO₂), commonly colored red-orange by iron oxides. The specimen may include opaque jasper or agate zones.

Black Onyx

Silicon Dioxide (SiO2) - variety of Chalcedony

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (composed primarily of Quartz, SiO2)

Sandstone (Ferruginous)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)

Corundum (Sapphire/Ruby in Matrix)

Aluminium oxide (Al2O3)

Possible iron-rich basalt or industrial slag

Basalt, likely Fe–Mg silicate rock; exact identification is uncertain from the blurred image

Sandstone Beach Pebble

Clastic Sedimentary Rock (primarily Quartz with Iron Oxide coating)

Blue Agate (Tumbled and Dyed)

Silicon Dioxide (SiO2) with likely organic dyes

Dark volcanic pebble, likely basalt

Basalt; fine-grained mafic rock composed mainly of plagioclase, pyroxene, and commonly olivine or magnetite

Fluorite (specifically Blue John or Banded Fluorite)

Calcium Fluoride (CaF2)

Clear Quartz (Rock Crystal Fragments)

Silicon Dioxide (SiO2)