Buying gold on Dhanteras is considered auspicious because it's believed to invite wealth and prosperity. The day marks the start of Diwali and honours Goddess Lakshmi, the goddess of wealth. The term 'Dhanteras' comes from 'Dhan' (wealth) and 'Teras' (thirteenth day). Buying gold on this day is said to attract Goddess Lakshmi's blessings and good fortune.