Notes:

By visualkid-n

Source I
Source II

I was inspired to draw this by this Wikipedia article about St. John’s Island (also known as Zabargad, Zebirget, Topazios, Gazirat Zabarjad): the largest of a group of islands in Foul Bay, Red Sea in southern Egypt where peridot as a mineral was mined in ancient times.

The island comprises three massives of peridotite, which are rich in the gemstone peridot (olivine). This gem makes the island notable as it is believed to be the first discovered source of peridot, which was called topazios in ancient times, hence the Greek name for the island, Topazios. Layers of spinel-lherzolites with anhydrous Al-diopside pyroxenites and hydrous Cr-diopside pyroxenites can be found too on the island. The presence of all of these minerals has led to mining on the island which dates back as early as ancient times.