Rock (Likely Sedimentary)

Light-colored quartz-rich stone, possibly milky quartz

Quartz (SiO₂), provisional identification

River Pebble (Gneiss or Quartzite variant)

Course-grained Metamorphic Rock (likely SiO2 dominant)

Fossil coral fragment (probable)

Recrystallized fossil coral, commonly scleractinian or tabulate coral; exact identification requires magnification and locality

Basalt

Vesicular Basalt

Weathered quartz-rich rock, possibly sandstone or quartzite

Indeterminate; likely quartz sandstone (SiO₂-rich), possibly weakly metamorphosed quartzite

Granite with Tourmaline or Biotite

Phaneritic Igneous Rock (Granoid)

Granite Cobble

Phaneritic Felsic Igneous Rock

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Precious Opal

Hydrated Silica (SiO2·nH2O)

Basalt River Stone with Mineral Crust

Aphanitic Mafic Igneous Rock

Weathered granitic rock (likely biotite granite)

Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite mica

Limestone with Fossil inclusions

Fossiliferous Limestone (CaCO3)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica (possibly gneissic if foliation is confirmed)

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered gray-green pebble

Indeterminate; possibly altered basalt, serpentinite, or a greenish metamorphic rock

Sandstone pebble

Sandstone (mainly Quartz, SiO2)

Likely basalt or other dark igneous rock

Basalt; predominantly plagioclase feldspar and pyroxene, possibly olivine

Weathered limestone fragment

Limestone, predominantly calcite (CaCO₃)

Iridescent schist or phyllite

Micaceous quartz-rich schist/phyllite, likely containing muscovite or chlorite

Polished green stone, likely serpentine or altered basalt

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; exact identification requires testing

Metallic sulfide-bearing rock, possibly galena-rich ore

Likely galena (PbS) with iron sulfides and quartz/rock matrix; exact identification requires testing

Mixed Gemstone and Mineral Collection

Mixed Silica and Carbonate minerals (SiO2, CaSO4·2H2O, etc.)

Dyed Agate

SiO2 (Silicon Dioxide)

Chert (Jasper)

Silicon Dioxide (SiO2)

Andesite Porphyry

Porphyritic Andesite (Intermediate volcanic rock)

Basalt (Porphyritic Basalt)

Porphyritic Basalt (Mafic volcanic rock)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with iron-oxide staining and minor feldspar or mica

Agate (or Chalcedony with Moss/Jasper Inclusions)

Silicon Dioxide (SiO2)

Pumice

Pumice (Amorphous volcanic glass)

Possible basaltic rock or meteorite candidate

Likely vesicular basalt; meteorite identification cannot be confirmed visually

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

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

Quartz (SiO₂), potentially microcrystalline quartz (chalcedony)

Pink granite

Granite, chiefly quartz–alkali feldspar–plagioclase with biotite/hornblende

Possible weathered quartz-rich rock or iron-stained mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide inclusions

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Vesicular basalt (likely weathered volcanic rock)

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine

Shale

Fissile mudrock (composed of clay-sized particles and detrital grains)

Red Sandstone

Clastic Sandstone (typically Quartz-rich with Iron Oxide)

Fossil Shell

Invertebrate fossil (Mollusca)

Weathered sandstone or tuff fragment

Likely quartz-rich sandstone (SiO₂) or porous volcanic tuff; exact identification requires testing

Likely basalt or scoria fragment

Dark mafic volcanic rock, most likely basalt (plagioclase–pyroxene–olivine) or vesicular scoria