Why some months of the year have two birthstones?

Question

Why some months of the year have two birthstones?

Answer 1

I just learned here that each month has several birth stones.  I did not know January had two.  I knew garnet was one, but did not know that lapis lazuli was another one.  Just scroll down throughout each month and you will see all the birth stones. http://fashion-era.com/calendar_months/1...