Topazos Ancient Name for Peridot

Topazos Discovered Around 300 BC
The green gemstone known today as peridot was once called topazos. It's believed to have been discovered around 300 BC on St. Johns Island or Zabargad as it's known in Arabic.
In historical references the names Topazos and Topazios are both used in relation to the island and the gemstone peridot.
In John Bostock's translation of Pliny the Elder's works Naturalis Historia both are referred to as "topazos". Topazios is likely to have come from the Greek word for 'topaz' which is 'tοpáziοs'.
In most cases where the word topaz has been used historically it's believed the stone is probably peridot. The mineral known today as topaz is not believed to have been known much before the 1700's.