Agate
This is hard and coloured natural rock made up of various varieties of silica, e.g. quartz, and chalcedony containing hyaline quartz and amethyst.
It is very hard and easy to polish and is used to manufacture mortars and pestles.
Agate
This is hard and coloured natural rock made up of various varieties of silica, e.g. quartz, and chalcedony containing hyaline quartz and amethyst.
It is very hard and easy to polish and is used to manufacture mortars and pestles.