Mineral (Chalcedony)

Tumbled blue chalcedony (likely blue quartz/chalcedony)

Cryptocrystalline silica, SiO₂; likely chalcedony, possibly dyed or surface-coated

Tumbled brown quartz/chalcedony (probable)

Quartz, SiO₂; possibly brown chalcedony or jasper

Tumbled amber-colored chalcedony and quartz

Chalcedony (microcrystalline SiO₂), quartz (SiO₂), possibly carnelian or citrine; one piece may be druzy chalcedony

Polished bloodstone (heliotrope), likely

Cryptocrystalline quartz (chalcedony, SiO₂) with iron-oxide inclusions

Tumbled amber-brown chalcedony (probable carnelian/ag ate)

Microcrystalline quartz, SiO₂; likely iron-stained chalcedony (carnelian)

Tree Agate

Chalcedony (SiO2)

Chalcedony (River Agate)

Silicon Dioxide (SiO2)

Gray chalcedony (possibly common opal)

Microcrystalline quartz, SiO₂; potentially hydrated silica, SiO₂·nH₂O

Tumbled chalcedony or agate fragment

Microcrystalline quartz (SiO₂), likely chalcedony; exact identification is limited by the small, opaque image

Tumbled chalcedony (likely yellow/brown agate or carnelian)

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

Tumbled brown chalcedony or jasper

Microcrystalline quartz, SiO₂; possibly iron-bearing jasper

Tumbled brown jasper or chalcedony

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

Tumbled brecciated jasper

Microcrystalline quartz (SiO₂), commonly with iron-oxide and other mineral inclusions

Tumbled jasper or chalcedony pebble

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

Tumbled yellow chalcedony (likely citrine or yellow jasper)

Cryptocrystalline quartz, SiO₂; exact identification requires testing

Orange chalcedony / agate fragment

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony

Chalcedony (Common Opal variant or Agate)

Silicon Dioxide (SiO2)

Chalcedony Nodule in Matrix

Silicon Dioxide (SiO2)

Agate

SiO2

Polished carnelian/chalcedony

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony

Polished pink-orange chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; carnelian is orange-red chalcedony

Likely quartz-rich chalcedony or agate fragment

Microcrystalline quartz (SiO₂), possibly iron-oxide-stained chalcedony/agate

Orange chalcedony (carnelian-like), possibly iron-stained quartz

Microcrystalline quartz, SiO₂ (chalcedony); orange coloration likely from iron oxides/hydroxides

Agate

Chalcedony (SiO2)

Chalcedony (probably agate or common quartz)

Microcrystalline quartz, SiO₂

Quartz Geode (partially formed/chalcedony with iron staining)

Quartz (SiO2) with Chalcedony (cryptocrystalline quartz) and likely Iron Oxides/Hydroxides

Blue Chalcedony

Chalcedony (SiO2)

Agate

Chalcedony (SiO2)

Red jasper (likely)

Microcrystalline quartz, SiO₂, colored red by iron oxides

Dyed Agate

Chalcedony (SiO2)

Blue Chalcedony

Chalcedony (SiO2)

Chalcedony (Botryoidal or Tumbled)

Chalcedony (SiO₂)

Blue Chalcedony

Chalcedony (SiO2)

Yellow-orange chalcedony (possibly carnelian)

Microcrystalline quartz, SiO₂; orange coloration commonly from iron oxides

Tumbled amber-colored agate or chalcedony

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

Tumbled gray-blue agate/chalcedony

Microcrystalline quartz (SiO₂), likely banded chalcedony or agate

Tumbled pink chalcedony (likely pink agate/jasper)

Microcrystalline quartz, SiO₂, with iron-oxide coloring

Tumbled carnelian/chalcedony

Chalcedony (microcrystalline quartz), SiO₂; reddish color from iron oxides

Polished jasper-like stone

Likely chalcedony (microcrystalline quartz, SiO₂), possibly brecciated jasper

Tumbled jasper (likely picture jasper)

Jasper, an opaque microcrystalline variety of quartz (SiO₂); exact variety uncertain from the photo

Tumbled jasper (likely)

Microcrystalline quartz, SiO₂; likely jasper, a variety of chalcedony

Tumbled carnelian agate

Carnelian, a reddish-orange variety of chalcedony (microcrystalline quartz, SiO₂)