Roofing Granules - Rock Granuels

This artifact is a set of five different colored rock granuels encapsulated in plastic. Donor's Remarks:  This artifact is courtesy of Mr. Robert E. Spencer, PHR - 3M Industrial Mineral Products Division - P. O. Box 1328 - Corona, Calif. - 01718 - 909.737.9441.
Abstract/Description: This artifact is a set of five different colored rock granuels encapsulated in plastic. Donor's Remarks: This artifact is courtesy of Mr. Robert E. Spencer, PHR - 3M Industrial Mineral Products Division - P. O. Box 1328 - Corona, Calif. - 01718 - 909.737.9441.
Subject(s): MINES AND MINING - In General
Corona, CA