What is the difference between zodiac and birth stones?

what is the difference between them?? my birthstone is peridot and sun or zodiac stone is Sapphire?? and i was born in august 25...|||Month's birthstones lag Zodiac by one "month." That is because 2/3 rds of a zodiac sun sign is in the month following the 1st decant of the zodiac. IF your Birthstone is Peridot, you are a 1st decant Virgo (born Aug 22 - 31) Your lucky stone will be Sapphire. I would not place a lot of emphasis on birthstone/Zodiac Stone as to luck or anything else other than a piece of jewelry. For the most part, we make our own luck. (Signed, a 1st decant Virgo, Aug 31, who uses Sapphire as his stone)