Certain gem stones have more vibration power at certain times of the year. The month of a stone's power time determines your birthstone (also referred to as natal stone).
Some believe that the original associations between gemstones
and the months of the year evolved from 12 stones mentioned in the Bible, others say it represents the Twelve Apostles. Still others hold different beliefs. There are numerous traditions over the centuries that connect a particular gemstone with a month of the year.