Probably the ancient topaz of a golden colour. Re 21:20. The Greek word ?????????? occurs in the LXX in Ex 28:20; 36:20 (Ex 39:13); Eze 28:13.
the fourth an emerald, the fifth sardonyx, the sixth sardius, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprasus, the eleventh jacinth, the twelfth an amethyst.