LABORATORY. FRANK SANBORN, Mineral Technologist. Letters are frequently received at this bureau from prospectors who seek information as to how certain minerals can be identified in the field. It is not always easy to give simple and satisfactory replies to these inquiries, for some minerals, such as the aluminum silicates which are now in demand, are not always readily identified even when a wellequipped laboratory is at hand. Many of the samples received at the bureau's laboratory are merely more or less decomposed or altered. rocks having no commercial value. There are some of the physical properties of minerals that can be easily learned by a prospector, and by learning these properties it is possible that the worth-while minerals can be identified and prospecting made more interesting. Hardness. With a little practice the hardness of a mineral can be estimated rather closely by the ease with which it can be scratched with a knife blade. In the scale of hardness generally used a knife blade has a hardness of a little over 5, while ordinary window glass is usually a little harder, having a hardness of about 5.5; therefore a knife blade will not readily scratch glass. Quartz has a hardness of 7, consequently a knife blade. will not scratch quartz, but the quartz will readily scratch glass. Moh's scale of hardness is as follows: Tale (1), Gypsum (2), Calcite (3), Fluorite (4), Apatite (5), Feldspar (6), Quartz (7), Topaz (8), Corundum (9). Diamond (10). Gypsum with a hardness of 2 can be scratched with the finger nail. A copper coin has a hardness of 3, and a pin point has a hardness of about 3.5. Care must be taken to distinguish between a mark left by one mineral on another and a scratch. Cleavage. Many minerals when struck a sharp, quick blow with a hammer, have the property of breaking with smooth surfaces in certain. directions which are parallel to actual or possible crystal faces. This property is called cleavage, and it may be exhibited in only one direction as in mica, or in several directions as in calcite. Common cleavages are: 'cubic' as shown when a cube of galena is fractured, and 'rhombohedral' as when a piece of calcite is cleaved. Mica exhibits a good example of 'basal' cleavage, and feldspars have a cleavage in two directions, at, or nearly at right angles, while quartz has no cleavage. Specific Gravity. The specific gravity of a substance is the ratio of its weight to the weight of an equal volume of water, the weight of water being taken as 1.0. Thus quartz has a specific gravity of approximately 2.6 which means that it is 2.6 times heavier than the same volume of water. Lead has a specific gravity of 11.37 and is therefore 11.37 as heavy as an equal volume of water. The mineral barite has a specific gravity of 4.5 and can be distinguished from limestone and other common minerals which it resembles by its 'heavy feeling,' calcite having a specific gravity of 2.72. Streak. The 'streak' of a mineral is merely the color of its powder. A piece of chert or quartz will often answer as a streak-plate. By rubbing a piece of hematite on a piece of quartz a red powder will adhere to the quartz, yellow for limonite, brown for chromite, etc. Panning. Many minerals of value though disseminated through a rock can be concentrated by panning. The material to be tested in this way should be ground to a uniform size if possible, and panned carefully in a clean pan (a small frying or egg pan, free from grease, makes an excellent gold pan). In panning, care should be taken not to mistake little fragments of the mortar or pestle for a mineral. It is a good policy to use a magnet on the concentrates, if there is any doubt as to whether or not they are of iron. By careful panning a great many minerals can be concentrated and subsequently identified. Panning should not be considered merely as a method for detecting only gold in rock, for when carefully manipulated, a gold pan can bring to light most of the minerals having a higher gravity than quartz. The State Mining Bureau endeavors to assist prospectors in every way, and will gladly advise in specific cases. During the four-month period covered by this report 1292 samples were received and determined at the laboratory. LIBRARY. FOREST L. CAMPBELL, Librarian. In addition to the numerous standard works, authoritative information on many phases of the mining and mineral industry is constantly being issued in the form of reports and bulletins by various government agencies. The library of the State Mining Bureau contains some five thousand selected volumes on mines, mining and allied subjects, and it is also a repository for reports and bulletins of the technical departments of federal and state governments and of educational institutions, both domestic and foreign. It is not the dearth of the latter publications, but rather a lack of knowledge of just what has been published and where the reports may be consulted or obtained, that embarrasses the ordinary person seeking specific information. To assist in making the public acquainted with this valuable source of current technical information, 'Mining in California' contains under this heading a list of all books and official reports and bulletins received, with names of publishers or issuing departments. Files of all the leading technical journals will be found in the library, and county and state maps, topographical sheets and geological folios. Current copies of local newspapers published in the mining centers of the State are available for reference. The library and reading room are open to the public during the usual office hours, when the librarian may be freely called upon for all necessary assistance. Governmental. OFFICIAL PUBLICATIONS RECEIVED. U. S. Geological Survey: Bulletin No. 750-B-Origin of Certain Rich Silver Ores Near Chloride and Kingman, Arizona. By E. S. Bastin. Bulletin No. 752-Coal Resources of the Raton Coal Field, Colfax County, New Mexico. By W. T. Lee. Water Supply Paper No. 489-The Occurrence of Ground Water in the United States. By O. E. Meinzer. Water Supply Paper No. 492-Summary of Hydrometric Data in Washington, 1878-1919. By G. L. Parker. Water Supply Paper No. 498-The Lower Gila Region, Arizona. By Clyde P. Ross. Water Supply Paper No. 502-Surface Water Supply of the United States, 1919 and 1920. Part II, South Atlantic Slope and Eastern Gulf of Mexico Basins. By Nathan C. Grover. Water Supply Paper No. 505-Part V, Hudson Bay and Upper Mississippi River Basins. By Nathan C. Grover. Water Supply Paper No. 511-Part XI, Pacific Slope Basins in California. By N. C. Grover. Water Supply Paper No. 524-Part IV, St. Lawrence River Basin. By Nathan C. Grover. Water Supply Paper No. 528-Part VIII, Western Gulf of Mexico Basins. By N. C. Grover. Water Supply Paper No. 497-The Salton Sea Region, California. By John S. Brown. Mineral Resources of the United States: Copper in 1922. Gold, Silver, Copper, Lead and Zinc in Nevada in 1922. Manganese and Manganiferous Ores in 1922. Gold, Silver, Copper, Lead and Zinc in Montana in 1922. Gold, Silver, Copper, Lead and Zine in Arizona in 1922. Gold, Silver, Copper, Lead and Zinc in Oregon and California in 1922. Cobalt, Molybdenum, Nickel, Tantalum, Titanium, Tungsten, Radium, Uranium and Vanadium in 1922. U. S. National Museum (Smithsonian Institution): Bulletin 100-The Polyclad Turbellarians from the Philippine Islands. Proceedings of the U. S. National Museum, Vol. 62. Annual Report of the National Museum, 1923. U. S. Bureau of Mines: By Bulletin No. 221-Production and Briquetting of Carbonized Lignite. By E. J. Babcock and W. W. Odell. Bulletin No. 212-Analytical Methods for Certain Metals Including Cerium, Thorium, Molybdenum, Tungsten, Radium, Uranium, Vanadium, Titanium and Zirconium. By R. B. Moore and others. Bulletin No. 230-Analysis of Samples of Delivered Coal. By N. H. Snyder. Bulletin No. 223-An Investigation of Powdered Coal as Fuel for Power Plant Boilers. By Henry Kreisinger and others. Technical Paper No. 310 Recovery of Gasoline Vapors. By D. B. Dow. from Uncondensed Still Technical Paper No. 324-Uses of Water in the Oil-Shale Industry. By J. J. Lakosky. Technical Paper No. 344-Analysis of Ohio Coals. Technical Paper No. 350-Accidents at Metallurgical Works in the United States During 1922. By W. W. Adams. Technical Paper No. 354-Metal-Mine Accidents in the United States in 1922. By W. W. Adams. Technical Paper No. 337-Carbon Monoxide Hazards from House Heaters Burning Natural Gas. By G. L. Jones. Reports of Investigations : Serial No. 2550-The Paraffin Problem in Oil Wells By R. Van A. Mills. Serial No. 2552-Explosives Used in October, 1923. By W. W. Adams. Spon Serial No. 2554-Cooling of Mine Air. By T. T. Read and F. C. Houghten. Serial No. 2555-Oxygen-Oil Explosions. Preliminary Report III. taneous Ignition of Oils in Oxygen Under Pressure. By S. H. Brooks. Serial No. 2556-Ferric Sulphate and Sulphuric Acid from Sulphur Dioxide and Air. By Edmund S. Leaver and R. V. Thurston. Serial No. 2557-Industrial Accidents in the California Oil Fields. By H. C. Serial No. 2558-Methods of Testing Detonators. By C. A. Taylor and C. E. Serial No. 2564-Conductivity and Specific Heat of Refractories at High Temperatures. By Mayo D. Hersey and Edward W. Butzler. Serial No. 2565 The Kata Thermometer; its Value and Defects. By W. J. McConnell and C. P. Yaglaglou. Serial No. 2566–Third Mine-Rescue Maneuvers at Globe, Arizona. By F. C. Gregory. Serial No. 2567-The Danger of Open Lamps in Coal Mines. By L. C. Ilsley, and M. W. von Bernewitz. Serial No. 2568-Subject List of Reports of Investigations Issued During 1923. Serial No. 2570-A Float-and-Sink Method and Apparatus for Testing Coarse- Natural-Gas Heaters Investigated by the Bureau of Mines in the Pittsburgh District During the Past Year. By G. W. Jones and W. P. Yant. Serial No. 2573-Explosives Used in December, 1923. By W. W. Adams. Serial No. 2574-Coal-Mine Fatalities in January, 1924. By W. W. Adams. Serial No. 2575-Tests of Lignite Char as Reduction Fuel in the Smelting of Zinc Ores. By B. M. O'Harra. Serial No. 2576-Underground Signalling for Mines by the Ground-Conduction or "T.P.S." Method. By J. J. Jakosky. Serial No. 2577-Ninth Semi-Annual Motor Gasoline Survey. By N. F. Serial No. 2578-A Process for the Production of Sponge Iron. By Clyde E. Williams, Edward P. Barrett and Bernard M. Larsen. Serial No. 2579-Mine-Accident Statistics. By W. W. Adams. U. S. Department of Commerce, Bureau of Standards: Technologic Paper No. 241-A Comparison of the Deoxidation Effects of Titanium and Silicon on the Properties of Rail Steel. By G. K. Burgess. Circular No. 148-U. S. Government Specifications for Leather Belting. National Research Council: No. 49-Statement of Activities for the Year Ending June 30, 1923. California State Department of Public Works, Division of Engineering: Bulletin No. 4-Water Resources of California. Bulletin No. 5-Flow in California Streams. Bulletin No. 6-Irrigation Requirements of California Lands. Bulletin No. 7-California Irrigation District Laws. Mississippi State Geological Survey: Ninth Biennial Report of the Director, 1921 1923. Missouri Bureau of Geology and Mines: Vol. XVII-The Devonian of Missouri. By E. B. Branson. Biennial Report of the State Geologist, 1921. Biennial Report of the State Geologist, 1923. Vol. XVI-The Occurrence of Gas and Oil in Missouri. By M. E. Wilson. North Carolina Geological and Economic Survey: Bulletin No. 33-The Deep River Coal Field of North Carolina. By M. R. Campbell and K. W. Kimball. Vol. V-The Cretaceous Formations of North Carolina. North Dakota Geological Survey: Bulletin No. 2-Artesian Water Conditions in North Dakota. By H. E. Simpson. Ohio, Geological Survey of: Bulletin No. 26-Coal Formation Clays. By Wilbur Stout. Bulletin No. 27-Geography of Ohio. By R. J. Peattie. Washington Geological Survey: Bulletin No. 20-The Mineral Resources of Stevens County. By Chas. E. Weaver. Bulletin No. 21-The Mineral Resources of Washington with Statistics for 1919. By E. N. Patty and S. L. Glover. Bulletin No. 23-The Metal Mines of Washington. By E. N. Patty. |