Golconda Diamond

The Golkonda Fort used to have a vault where once the famous Kohinoor and Hope diamonds were stored along with other diamonds.
Golkonda was once renowned for the diamonds found on the south-east at Kollur Mine near Kollur (modern day Guntur district), Paritala (modern day Krishna district) and cut in the city during the Kakatiya reign. At that time, India had the only known diamond mines in the world.

Golkonda's mines yielded few diamonds. Golkonda was the market city of the diamond trade, and gems sold there came from a number of mines. The fortress city within the walls was famous for diamond trade. However, Europeans believed that diamonds were found only in the fabled Golkonda mines.
Magnificent diamonds were taken from the mines in the region surrounding Golkonda, including Darya-e Nur, meaning sea of light, at 185 carats (37.0 g), the largest and finest diamond of the crown jewels of Iran.
Its name has taken a generic meaning and has come to be associated with great wealth. Gemologists use this classification to denote a diamond with a complete (or almost-complete) lack of nitrogen; "Golkonda" material is also referred to as "2A".

Many famed diamonds are believed to have been excavated from the mines of Golkonda, such as:
Darya-e Nur
Nur-Ul-Ain Diamond
The Koh-i-noor
The Hope Diamond
Princie Diamond
The Regent Diamond
Wittelsbach Diamond

By the 1880s, Golkonda was being used generically by English speakers to refer to any particularly rich mine, and later to any source of great wealth.
During the Renaissance and the early modern eras, the name "Golkonda" acquired a legendary aura and became synonymous for vast wealth. The mines brought riches to the ruling Qutb Shahis of Hyderabad State, who ruled Golkonda up to 1687, then to ruling Asaf Jah of Hyderabad State, who ruled after the independence from the Mughals in 1724, until 1948, when Hyderabad was annexed, to become an Indian state.