Sedimentary (Volcanic)

Tumbled jasper/chalcedony pebbles

Microcrystalline quartz (SiO₂), likely jasper and brown chalcedony

Polished red jasper

Jasper, microcrystalline quartz (SiO₂), colored by iron oxides and commonly mixed with chalcedony or other minerals

Red jasper (tumbled)

Jasper, microcrystalline quartz/chalcedony (SiO₂) colored mainly by iron oxides

Carnelian

Silicon Dioxide (Chalcedony variety), SiO2

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) - variety of Chalcedony

Dendritic Agate

Dendritic Agate (Silicon Dioxide with Manganese or Iron Oxide inclusions, SiO2)

Carnelian

Carnelian (a variety of Chalcedony, SiO2) colored by iron oxide

Agate Geode

Cryptocrystalline Quartz (SiO2)

Agate (Turtle Carving)

Agate (Cryptocrystalline variety of Silica, SiO2)

Geode

Quartz / Chalcedony nodule

Banded sandstone pebble

Lithic or quartz-rich sandstone; exact composition requires testing

Polished Ocean Jasper (orbicular jasper)

Siliceous microcrystalline quartz/chalcedony, mainly SiO₂, with iron- and manganese-rich inclusions

Jasper (specifically Yellow/Red Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (specifically Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides (Goethite/Limonite)

Orange Moss Agate / Carnelian Agate

Silicon dioxide (SiO2) - variety Chalcedony

Yellow Jasper

Silicon Dioxide (SiO2) with iron impurities

Weathered sandstone or volcanic rock fragment

Indeterminate; likely quartz–feldspar-rich sandstone, possibly altered volcanic rock

Jasper

Silicon dioxide (SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Ocean Jasper

Silicon Dioxide (SiO2) with various inclusions

Agate

Silicon dioxide (Chalcedony), SiO2

Green Jasper

Silicon Dioxide (SiO2)

Chert (Common Opal/Agate mixture)

Microcrystalline Quartz (SiO2)

Bumblebee Jasper

Fossiliferous Calcite containing Orpiment and Realgar

Tumbled brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly with chalcedony and iron oxides

Porphyritic volcanic rock, likely andesite or rhyolite

Porphyritic andesite–rhyolite; chiefly plagioclase, quartz, and altered ferromagnesian minerals in a fine groundmass

Agate

Silicon Dioxide (Chalcedony), SiO2

Weathered mafic rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Vesicular basalt (likely scoria)

Basaltic volcanic rock, chiefly plagioclase, pyroxene, and often olivine

Porphyritic basalt or andesite

Porphyritic volcanic rock; typically plagioclase phenocrysts in a fine mafic/intermediate groundmass

Blue Agate Slice

Chalcedony (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Porphyritic basalt or andesite pebble

Porphyritic volcanic rock; commonly plagioclase phenocrysts in a fine mafic-to-intermediate matrix

Porphyritic volcanic rock (likely andesite or basaltic andesite)

Porphyritic andesite/basaltic andesite; mainly plagioclase, pyroxene, and possibly olivine in a fine volcanic groundmass

Unidentified dark gray rock fragment

Likely fine-grained basalt or andesite; exact identification requires testing

Weathered vesicular basalt (likely amygdaloidal basalt)

Basalt, composed mainly of plagioclase feldspar, pyroxene, and altered olivine; cavities may contain secondary zeolite, calcite, or silica

Quartz Geode

Silicon dioxide (SiO2)

Likely polished leopard-skin jasper or brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide and other mineral inclusions; exact variety cannot be confirmed from the image alone

Red Jasper (or Banded Jasper)

Silicon Dioxide (SiO2 with Hematite impurities)

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides

Rough amber-like brown mineral specimen

Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber