Pomeroy Tucker writes that the white stone was found in a well; used in fortune-telling and "seership."
Pomeroy Tucker, Origins, Rise, and Progress of Mormonism (New York: D. Appleton and Co., 1867), 19-20
In September, 1819, a curious stone was found in the digging of a well upon the premises of Mr. Clark Chase, near Palmyra. This stone attracted particular notice on account of its peculiar shape, resembling that of a child's foot. It was a whitish, glassy appearance, though opaque, resembling quartz. Joseph Smith, Sr., and his elder sons Alvin and Hyrum, did the chief labor of this well-digging, and Joseph, Jr., who had been a frequenter in the progress of the work, as an idle looker-on and lounger, manifested a special fancy for this geological curiosity; and he carried it home with him, though this act of plunder was against the strenuous protestations of Mr. Chase's children, who claimed to be rightful owners. Joseph kept this stone...Very soon the pretension transpired that he could see wonderful things by its aid. The idea was rapidly enlarged upon from day to day, and in a short time his spiritual endowment was so developed that he asserted the gift and power (with the stone at his eyes) of revealing both things existing and things to come. For a length of time this clairvoyant manifestation was sought to be turned to selfish advantage, in the way of fortune-telling, and in the pretended discovery by the medium of the seer-stone of lost or stolen property.