Stone of Headington Headington stone is a limestone found near Oxford, England's Headington Quarry region. It was used to build many of the city's colleges and schools. Headington stone is a fine, hard, compact limestone. The best known face has a light gray color caused by the presence of micas (minerals with the chemical formula K, Na, Mg, Ca, or Al). These minerals give the stone some degree of hardness and resistance to erosion. But they also cause Headington stone to be white rather than green or brown like most other limestones. The Headington stone was used between 1290 and 1650. Thereafter it was replaced with chalk from the now-defunct White Horse Hill quarry, which is still visible in Headington village today. The stone is said to have been given its name because it came from a heading (i.e., pointed) hill. However, this explanation does not take into account the fact that there are several quarries around Headington where one might expect to find stone of different colors, but only white Headington stone can be found there.