In the Gregorian calendar, on which our current calendar is based on, a year was mathematically figured to be 365.2419 days long. It was calculated that 97 days would need to be added every 400 years in order to keep certain dates with certain seasons. It was agreed that an extra day would be added every 4th year. These are known as leap years. February's birthstone is an Amethyst.
Amethysts are violet in color.
Valentine's Day 4. Valentine's Day is on February 14th. Valentine's Day is named for Saint Valentine. During this time soldiers were ordered not to engage or marry. Valentine would secretly marry the soldiers to their loves.