Mineral (Chalcedony)

Tumbled agate/chalcedony pebble

Microcrystalline quartz (SiO₂), likely agate or jasper variety

Honey-colored chalcedony (rough agate/chert)

Microcrystalline quartz, SiO₂; likely chalcedony with iron-oxide staining

Blue Chalcedony

Chalcedony (a cryptocrystalline variety of Quartz - SiO₂)

Banded agate (likely a polished agate slice)

Microcrystalline quartz, chiefly chalcedony (SiO₂)

Tumbled agate and jasper specimens

Chalcedony (microcrystalline quartz, SiO₂), including agate and jasper varieties

Tumbled chalcedony or quartz pebble

Microcrystalline quartz, SiO₂ (likely chalcedony; exact identification requires testing)

Pink chalcedony (rose quartz–like quartz)

Microcrystalline quartz, SiO₂; possibly quartz-rich rhyolite or jasper

Polished banded jasper (likely red jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored by iron oxides; exact variety uncertain

Tumbled dendritic agate (likely)

Chalcedony, microcrystalline SiO₂, with dark manganese/iron-oxide inclusions

Tumbled brown jasper

Microcrystalline quartz (chalcedony), SiO₂; likely jasper

Botryoidal chalcedony (likely agate/jasper variety)

Microcrystalline quartz, SiO₂

Tumbled chalcedony (likely carnelian/opaque agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining

Dendritic agate cabochon

Chalcedony (microcrystalline quartz, SiO₂) with manganese-oxide dendrites

Honey/brown agate (chalcedony)

Microcrystalline quartz, SiO₂; likely translucent agate or chalcedony

Blue chalcedony cabochon (likely)

Chalcedony, microcrystalline SiO₂; possibly blue agate or common opal, which cannot be distinguished confidently from the image

Tumbled brown agate/chalcedony (probable)

Microcrystalline quartz, SiO₂; likely iron-stained agate or jasper

Tumbled yellow chalcedony (likely citrine-like quartz or yellow jasper)

Microcrystalline quartz, SiO₂; exact identification requires testing

Tumbled amber-colored chalcedony or jasper

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper

Grey Chalcedony (Tumbled Moon)

Microcrystalline Quartz (SiO2)

Chalcedony (Blue Dragon/Gray Chalcedony)

Silicon Dioxide (SiO₂)

Tumbled yellow chalcedony or calcite

Cryptocrystalline quartz (SiO₂), possibly yellow chalcedony; an alternative is yellow calcite (CaCO₃)

Tree Agate

Silicon dioxide (SiO2)

Chalcedony (Botryoidal Agate vein)

Chalcedony (Microcrystalline Quartz) - SiO2

Banded agate

Chalcedony, microcrystalline SiO₂

Botryoidal chalcedony/geode fragment

Microcrystalline quartz, SiO₂, likely chalcedony with drusy quartz

Brown chalcedony (likely agate)

Microcrystalline quartz, SiO₂; chalcedony, possibly banded agate

Polished banded agate (likely carnelian and black agate)

Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide coloration

Chalcedony (Common Opal or Agate variant)

Silicon Dioxide (SiO₂)

Chrysoprase

Chalcedony (SiO2)

Blue Lace Agate (or similar Chalcedony)

SiO2 (Silicon Dioxide)

Blue Chalcedony and Picture Jasper Beads

Blue Chalcedony (SiO2), Picture Jasper (SiO2)

Blue Chalcedony Cube

Silicon Dioxide (SiO2)

Agate

Chalcedony (cryptocrystalline quartz)

Green tumbled agate (likely green chalcedony)

Chalcedony, microcrystalline quartz (SiO₂); exact identification is uncertain from the photo

Geode

Quartz / Chalcedony nodule

Polished agate with black chalcedony inclusion

Banded chalcedony (microcrystalline quartz, SiO₂), likely agate or onyx-type material

Brown chalcedony (likely carnelian/iron-stained quartz)

Microcrystalline quartz, SiO₂; brown coloration from iron oxides/hydroxides

Agate Geode Nodule

Chalcedony / Quartz (SiO2)

Tumbled brown agate (likely carnelian/chalcedony)

Microcrystalline quartz, SiO₂; chalcedony, possibly iron-stained

Tumbled agate or chalcedony pebble

Microcrystalline quartz (SiO₂), likely agate/chalcedony

Orange chalcedony (possibly carnelian)

Microcrystalline quartz, SiO₂; iron-oxide-bearing chalcedony

Tumbled amber-colored chalcedony

Chalcedony (microcrystalline quartz, SiO₂), possibly yellow jasper or resinous amber-colored agate