Sardonyx is a variant in which the coloured bands are sard (shades of red) rather than black. Black onyx is perhaps the most famous variety, but is not as common as onyx with coloured bands. Artificial treatments have been used since ancient times to produce both the black colour in "black onyx" and the reds and yellows in sardonyx. Most "black onyx" on the market is artificially coloured. Onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items. Use of sardonyx appears in the art of Minoan Crete, notably from the archaeological recoveries at Knossos. Onyx is also mentioned in the Bible at various points, such as in Genesis 2:12 "and the gold of that land is good: there is bdellium and the onyx stone", and such as the priests' garments and the foundation of the city of Heaven in Revelation.