Mineral, Potentially A Rock With Chalcedony

Chalcedony or Chert/Jasper with secondary mineral staining

SiO2 (for chalcedony/quartz) with possible secondary copper minerals (e.g., CuSiO3·nH2O for chrysocolla, Cu2(CO3)(OH)2 for malachite) or iron oxides/hydroxides.

Quartz-rich rock fragment

Microcrystalline quartz (SiO₂), possibly chalcedony or quartz-bearing breccia

Milky Quartz Nodule / Geode precursor

Silicon Dioxide (SiO2)

Agate (specifically Waterline or Onyx-type Agate)

Silicon Dioxide (SiO2) - variety Chalcedony

Agate Geode Nodule

Chalcedony / Quartz (SiO2)

Quartz-rich translucent pebble, possibly iron-stained quartz or chalcedony

Quartz (SiO₂), potentially microcrystalline quartz (chalcedony)

Quartz geode

Crystalline quartz, silicon dioxide (SiO₂), lining a volcanic geode

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment

Small rounded pebble, likely quartz-rich river stone

Indeterminate; likely quartz/chert-bearing lithic clast

Likely weathered quartz-rich stone

Indeterminate; possibly quartz-bearing granite or milky quartz

Geode (unopened) or Calcareous Nodule

Siliceous or Calcareous Concretion/Nodule

Unknown Rock Specimen

Copper-bearing Quartz Vein in Host Rock

Quartz with Malachite/Chrysocolla staining

Quartz Vein in Basalt or Slate

Hydrothermal quartz vein traversing mafic host rock

Geode Nodules / Chert Pebble

Silicon Dioxide (SiO2) / Quartz concretion

Chert (Chalcedony/Agate variety)

Microcrystalline Quartz (SiO2)

Agate Geode (Unopened)

Cryptocrystalline Quartz (SiO2) with Chalcedony

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

Geode (Unopened)

Siliceous Septarian Concretion / Geode (SiO2)

Botryoidal quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Gold-bearing Quartz with Iron Oxides

Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)

Black Onyx

Chalcedony (SiO2 with inclusions)

Tumbled yellow chalcedony (likely citrine or yellow quartz)

Quartz, SiO₂; potentially microcrystalline chalcedony

Banded Jasper

Silicon Dioxide (SiO2) with impurities

Tumbled jasper or iron-rich chalcedony

Microcrystalline quartz (SiO₂), likely colored by iron oxides

Auriferous Quartz (Gold-bearing Quartz)

Silicon Dioxide (SiO2) with trace Gold (Au) and Iron Oxides

Chert (Common Opal/Agatized Rock)

Microcrystalline Quartz (SiO2) with potential Chalcedony/Opaline silica

Quartz Vein in Basalt or Sedimentary Host Rock

Silica-veined lithic fragment (SiO2 in host matrix)

Turritella Agate (Elimia Agate)

Silicified Elimia tenera (formerly misidentified as Turritella)

Unidentified gray stone

Likely quartz-rich stone; exact identification is not possible from the image

Black Onyx or Dyed Agate Node

Cryptocrystalline Quartz (SiO2)

Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)

AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition

Polished/tumbled quartz-rich pebble, possibly jasper or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂), potentially iron-stained jasper or quartzite

Pitted Sedimentary Rock / Cupstone

Sedimentary rock with weathering pit (arenite / sandstone)

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Quartz (Microcrystalline/Gravel)

Silicon Dioxide (SiO2)

Fossilized tooth or tooth fragment

Indeterminate vertebrate tooth; likely mammalian, mineralized hydroxyapatite

Chert (Nodule)

Chert (Silicon Dioxide, SiO2)

Chert (or potentially Jasper/Chalcedony)

SiO2 (Silicon Dioxide)

Black Onyx

Cryptocrystalline Quartz (SiO2)

Note: This is a Man-Made Object (Costume/Prop Patch)

Synthetic fiber and pigments (Cellulose/Plastic-based composite)

Agate with Fossil/Inclusion

Silicon Dioxide (SiO2) with chalcedony and potential fossil inclusion