These are varieties of chalcedony which have the most marked banding. The agate displays a contrast between the shading of the different bands, from pale to more intense colour. Stones can be beige, grey, white, blue, orange, black red or brown.
The fire Agata contains strata of chalcedony and transparent opal, the polisched surface reveals red and green iridescent flares similar to precious opals.
Amongst the most well known of Onyx is the sardonyx with white and dark coloured bands. Onyx can be brown, green, orange, pink or honey-coloured.