Organic Material (Likely A Fruit Or Berry)

Tumbled carnelian (likely chalcedony)

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

Quartz–mica metamorphic rock, likely schist

Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Iron meteorite fragment

Fe-Ni meteorite, likely an iron meteorite or stony-iron fragment

Petrified Wood

Silicified Wood (primarily SiO2)

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Fossilized Wood (with Coal and Limonite)

Petrified Wood (Silicified or Carbonized Flora)

Jasper

Jasper (Silica-rich microcrystalline Quartz, SiO2 with Fe2O3 impurities)

Siltstone or Mudstone

Argillaceous sedimentary rock

Blue chalcedony (likely dyed or polished)

Chalcedony, microcrystalline quartz (SiO₂)

Purple fluorite-bearing matrix specimen

Fluorite (calcium fluoride, CaF₂), likely with quartz and host-rock minerals

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with feldspar and accessory minerals; composition varies

Dark mafic rock, likely basalt

Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides

Shale with Vein Infillings

Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Petrified Wood with Lichen

Silicified Wood (SiO2) colonized by crustose lichens

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Jasper (specifically Yellow Jasper and Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Weathered iron-rich sandstone or lateritic rock

Ferruginous sandstone/laterite; chiefly quartz (SiO₂) with iron oxides such as hematite and goethite

Likely weathered sandstone or iron-stained sedimentary fragment

Quartz-rich sandstone; exact identification requires testing

Brown chalcedony (likely carnelian/agate)

Cryptocrystalline quartz, SiO₂; iron-bearing chalcedony

Chert (varieties: Flint or Chalcedony)

Microcrystalline Quartz (SiO2)

Coral (Precious Coral)

Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).

Biotite Schist (likely)

Biotite Schist (rock), Biotite (mineral)

Sandstone (Flagstone)

Arenite (composed primarily of SiO2)

Granite

Coarse-grained felsic intrusive igneous rock; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende

Siltstone with iron staining

Siltstone (primarily SiO2 with FeO(OH) coatings)

Yellow Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert (variations include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded calcite (likely marble or calcite-rich limestone)

Calcite, CaCO₃; possibly calcitic marble

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limestone Boulder

Sedimentary Rock (Calcium Carbonate, CaCO3)

Chert (Flint variety)

Microcrystalline Quartz (SiO2)

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

Speckled rounded stone, likely granite or granitic gneiss

Granite/granitic gneiss; primarily quartz (SiO₂), feldspar, and dark mica or amphibole

Chert (River Stone)

Silicon Dioxide (SiO2)

Tumbled black stone, likely basalt

Basalt; fine-grained plagioclase–pyroxene rock, possibly with magnetite