Tektite (Natural Glass)

Citrine Quartz

Citrine (Silicon Dioxide - SiO2)

Tumbled pink-and-white quartz

Quartz, silicon dioxide (SiO₂), likely rose quartz mixed with milky quartz

Orbicular rhyolite (likely)

Rhyolite, a silica-rich volcanic rock; commonly quartz, alkali feldspar, plagioclase, and iron-rich alteration minerals

Green Chalcedony (Batu Akik)

Silicon Dioxide (SiO2)

Granite

Felsic Plutonic Rock (Granite)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Rough Diamond (or Quartz Crystal)

Carbon (C) [if Diamond] / Silicon Dioxide (SiO2) [if Quartz]

Chert (Quartz Pebble)

Silicon Dioxide (SiO2)

Tumbled quartz-rich stone, likely milky quartz

Quartz (SiO₂), possibly iron-stained milky quartz or quartzite

Tumbled carnelian

Carnelian, orange-red variety of cryptocrystalline chalcedony (SiO₂)

Pyrite

Iron Disulfide (FeS2)

Red Jasper (Brecchiated Jasper)

Silicon Dioxide (SiO2) with Hematite impurities

Red jasper fragment

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

Chrome Diopside

Diopside (Magnesium Calcium Silicate) - CaMgSi2O6 + Cr

Quartzite Pebble

Quartzite (primarily SiO2)

Sandstone

Arenite (composed primarily of Quartz: SiO2)

Apache Tear

Obsidian (Hydrated Volcanic Glass - SiO2)

Basalt Pebble

Aphanitic mafic extrusive igneous rock

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

Chalcedony (likely common gray chalcedony)

Microcrystalline quartz, SiO₂

Rose Quartz

Silicon Dioxide (SiO2) with traces of titanium, iron, or manganese

Scoria (vesicular basalt)

Scoria; vesicular mafic volcanic rock, commonly basaltic in composition

Smoky quartz

Quartz (SiO₂), naturally irradiated brown variety

Amethyst

Silicon Dioxide (SiO2 with iron impurities)

Jasper (likely red/brown jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Jasper (Iron-rich Chert)

Silicon Dioxide (SiO2) with impurities of Hematite or Goethite

Tumbled pink quartzite or rose quartz

Quartz-rich quartzite; chiefly silicon dioxide (SiO₂), possibly with iron-bearing inclusions

Rose Quartz

Silicon Dioxide (SiO2) with trace impurities of Titanium, Manganese, or Iron

Likely chert or flint

Microcrystalline quartz (SiO₂), commonly called chert; exact identification requires testing

Polished malachite tower

Malachite, Cu₂CO₃(OH)₂ (basic copper carbonate)

Quartzite

Quartzite (primarily SiO2)

Yellow Aventurine

Quartzite with inclusions (SiO2)

Tumbled orange chalcedony (likely carnelian)

Carnelian, a cryptocrystalline variety of quartz (SiO₂)

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

Red Jasper (possibly Agatized Jasper)

Jasper (Silicon Dioxide, SiO2 with Fe2O3 inclusions)

Rounded sandstone pebble

Quartz-rich sandstone (likely arkosic or lithic sandstone)

Pebble (likely Quartzite or Chert)

Clastic Sediment, potentially composed of SiO₂ (Quartz)

Tumbled black stone, likely basalt or obsidian

Uncertain; likely fine-grained basalt (plagioclase–pyroxene) or dark volcanic glass (obsidian)

Tumbled chalcedony (likely pale agate or quartz pebble)

Microcrystalline silica, SiO₂ (chalcedony; possibly quartz-rich agate)

Likely serpentine pebble

Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄

Yellow chalcedony (likely heat-treated or resin-coated)

Microcrystalline quartz, SiO₂