Intense ultramarine blue gemstone. Soft but tough. The finest examples are found in Afghanistan, Lake Baikal, Bokhara and Turkestan.
Dark green Agate*, containing scattered spots of red jasper (Blood). Found in India, Siberia and the Hebridies.
Layered Agate* made up of a combination of Cornelianand White Chalcedony, Found in Uruguay, Brazil and Lake Superior.
Black, Exceedingly tough, Agate*.
Orangey-red Agate*. Found in Uruguay, Brazil and Lake Superior.
Layered Agate* made up of a combination of Onyx and White Chalcedony. See White/Red Sardonyx.
Agate is a tough cryptoctystalline variety of Quartz. It occurs in geodes in volcanic and sedimentary rocks and frequently as pebbles. It consists of chalcedony in which the colour is irregularly distributed. The colours are arranged in parallel bands called "banded Agates".