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 Geode Nodule

Chalcedony / Quartz (SiO2)

Agate (specifically Waterline or Onyx-type Agate)

Silicon Dioxide (SiO2) - variety Chalcedony

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

Quartz (SiO₂), potentially microcrystalline quartz (chalcedony)

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment

Quartz geode

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

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)

Unidentified gray stone

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

Turritella Agate (Elimia Agate)

Silicified Elimia tenera (formerly misidentified as Turritella)

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

Pitted Sedimentary Rock / Cupstone

Sedimentary rock with weathering pit (arenite / sandstone)

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

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

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

Quartz (Microcrystalline/Gravel)

Silicon Dioxide (SiO2)

Chert (Nodule)

Chert (Silicon Dioxide, SiO2)

Fossilized tooth or tooth fragment

Indeterminate vertebrate tooth; likely mammalian, mineralized hydroxyapatite

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