However, a water sapphire is iolite or cordierite. A balas ruby is spinel. A Madeira topaz is citrine. Evening emerald may be any green stone. German lapis is dyed chalcedony.
Mexican jade is dyed onyx.
Herkimer diamonds are quartz. New names are invented on a regular basis. As a consumer, you need to be aware that gemstones with additional names are substitutes and pay the appropriate price for them. Glass is a time-honored material for making artificial gems. Glass imitations have been found in Egyptian tombs which are at least 5,000 years old.