It lies at the northeastern edge of San Antonio Valley, along the border with Stanislaus County, California.

[3] One book claims that the deposits on the mountain are the purest known as of 2007,[3] although a USGS report notes that the quality varied between the veins.

[3] A number of magnesite veins are arranged conveniently around a small valley, visible from miles away due to their striking white color.

[5] Located on the Stanislaus County side of the mountain, and derived its water supply from a single, large spring.

[5] The magnesite from the mines was initially hauled down to Livermore by six-horse teams pulling to wagons, but one company was using large trucks by 1918.