This folder contains correspondence relating to mineral deposits, processes for the working of raw materials, and finished products. Among the metals and minerals mentioned in the documents are cullet (used broken glass), nickel sheets, feldspar, iron ore, selenium, cumerone resin, zinc, clay and lithium minerals, diamond bort, and slate. The correspondents include former Edison assistants and electric lighting pioneers William S. Andrews and William J. Hammer, Edison associate Theron I. Crane, geologist friends Henry C. Demming and George F. Kunz, Minnesota Geological Survey director William H. Emmons, Edison's brother-in-law Halbert K. Hitchcock of the Pittsburgh Plate Glass Co., and Ernest G. Liebold of the Ford Motor Co.

Approximately 30 percent of the documents have been selected. Among the items not selected are letters regarding business propositions and samples for testing that received no answer or a routine negative reply; items referred to chief engineer John P. Constable for analysis and reply; clay filtration test results submitted by T. Shriver & Co.; and price quotations on slate pieces. Also not selected are approximately thirty pages of unsigned notes on mines and minerals in South Dakota and on mineral extraction processes, which are closely related to the material in E-19-47 (Mining - General).