On the southern margin of the range and along the same northwest-southeast direction, there is a strip of Eocene rocks.

On the northwestern side of this strip, there is another section of Eocene rocks that are volcanic in origin.

[2] The well-known Nishabur turquoise comes from the weathered and broken trachytes and andesites of the Eocene volcanic rocks of this part of the mountain range.

The main turquoise mines are situated about 50 kilometres northwest of the city of Nishapur in the vicinity of a village called Madan.

[3] The range takes up the motion of Central Iran on the Arabian plate at the rate of 4.0 ± 1.3 mm (0.157 ± 0.051 in) per year.