White Chalcedony - White, pure microcrystalline quartz
(Left) Cornwall, England & (right) Mexico City, Mexico
Size: (Left) 10 cm, (Right) 4cm





Agate - Translucent, multicolored chalcedony with concentric banding
Sao Paulo, Brazil & China
Size: Left :3.5 cm / Right: 8 cm





Onyx - Agate with black and white bands.
New Mexico, USA & Mexico City, Mexico
Size: Left: 2.5 cm / Middle:5 cm / Right: 1.5cm





Chrysoprase - Green variety of chalcedony colored by nickel oxide
Queensland, Australia
Size: 6 cm





Aventurine - Translucent chalcedony with small green fuchsite (mica) inclusions.
Bangkok, Thailand
Size: Rock : 12 cm / Gem: 9mm





Moss Agate - Contains green mineral inclusions and lacks concentric banding, giving it the appearance of moss.

Size: 20 cm





Jasper - Opaque, red to brown chalcedony
Cairo, Egypt & Ural, Russia
Size: Left: 2 cm / Right: 6 cm





Bloodstone - Green chalcedony with patches of red jasper resembling drops of blood.
India
Size: 6 cm




Opal & Opal Cabochon
Tectosilicates
SiO2
Queensland, Australia
Size: 7cm (Opal), 7mm (Opan cabochon)





Opal
Tectosilicates
SiO2
Queensland, Australia
Size: 10 cm





Opal
Tectosilicates
SiO2
Queensland, Australia
Size: 20 cm






Thundereggs

They are completely filled nodules of agate which form in silica-rich volcanic rocks, eg. rhyolites. As the molten volcanic lava cooled, steam and other gases trapped in the lava formed an expanding bubble. Later, silica-rich solutions may enter the cavity and fill it with banded agate or chalcedony.

Size: 20 cm