The first association of a special gem with each month was recorded in the Bible. Exodus 28 and 39 describe how, in 1250 BC, Moses made a breastplate for the High Priest of the Hebrews according to instructions he received during 40 days in the mountains. The breastplate featured twelve gems which were later linked with the signs of the zodiac, and later still associated with the months in the year.
The breastplate is described as being square with four rows of precious stones: in the first row there was a ruby, a topaz and a beryl; in the second row a turquoise, a sapphire and an emerald; in the third row a jacinth, an agate and an amethyst and in the fourth row a chrysolite, an onyx and a jasper. Mounted in gold filigree settings, each of the were twelve stones - one for each of the names of the sons of Israel - was engraved like a seal with the name of one of the twelve tribes.