This stone wheel was used to sharpen the knives and blades that were used in the coin manufacturing process at the Real Casa de Moneda. It was a gift to the Real Casa de Moneda from the De Santos family.
The Real Casa de Moneda, or Royal Mint, is the original Spanish mint where all the coins in Spain where one produced. After the centralization of the manufacture of currency in Madrid in 1869, the building was sold, and from 1879 onwards a flour factory was housed for one hundred years.
The property has recently been renovated, and visitors can now enjoy its two museums, temporary exhibition halls, historic garden and channels with hydraulic wheels, guest house, restaurant and bar-cafeteria.