Who established the birthstones?

The birthstones that are recognized today were decided in 1912 by the National Jewelers Association. The idea of birthstones had been around for many centuries prior.

In Exodus, a breastplate worn by Aaron is described to have 12 different stones. Originally, these stones represented the tribe of Israel. Flavius Josephus was said to make the connection between the zodiac and the stones in the first century A.D. However, this connection meant that the wearer should wear each stone depending on the time of year. The current list was not created until 1912. This list assigns a certain stone for each month of the year.