In the Bible, when Moses went to Egypt, his brother Aaron stayed behind in their birth town in Egypt's far east. When Moses asked the King of Egypt to set his people free, it was Aaron who sold the idea to their kinsfolk.
Aaron became a high priest. His ceremonial breastplate held four
rows of three stones each. Exodus 28:17-20 states, "There were
twelve stones, one for each of the names of the sons of Israel, each
engraved like a seal with the name of one of the twelve tribes."
These 12 stones also symbolized the 12 months of the year and the 12
signs of the zodiac.
Biblical scholars have a difficult time translating exactly what
these stones are. The King James Bible lists the stones as: (Row 1)
sardius, topaz, carbuncle; (Row 2) emerald, sapphire, diamond; (Row
3) ligure, agate, amethyst; (Row 4) beryl, onyx, jasper. The New
American Standard Bible lists them as: (Row 1) ruby, topaz, emerald;
(Row 2) turquoise, sapphire, diamond; (Row 3) jacinth, agate,
amethyst; (Row 4) beryl, onyx, jasper.
The gems have changed a few times and different countries use
different stones. Below is the US version for 2012.
It was in 15th-century Poland that wearing these birthstones gained
popularity. In contrast to today's custom of wearing your birthstone
throughout the year, the early proponents owned a full set of 12 and
wore each month's stone, regardless of birthday. The Gemological
Institute of America says the custom began in Germany in the 1560s.