The term functions as a noun phrase, in which "gemstone" is the noun and "September 11th" is a compound adjective modifying it. The gemstone most directly associated with this date is the Sapphire, which is the established birthstone for the month of September.
Gemological and astrological traditions primarily assign gemstones to calendar months or zodiac signs rather than to specific dates. The date of September 11th falls within the astrological sign of Virgo (approximately August 23 to September 22). The primary gemstone for Virgo is also the Sapphire, reinforcing its designation. Other stones sometimes associated with the Virgo sign include carnelian, zircon, and peridot.
Therefore, based on the two dominant systems of gemstone attributionmonthly birthstones and zodiac signsthe Sapphire is the correct stone. Any assignment of a different gemstone to this specific calendar day would be based on alternative, non-traditional systems such as numerology or personal interpretation, not on established convention.
