by the U. S. Bureau of Foreign and Domestic Commerce, but for the nearly 10 months up to that time, the total was 112,159 long tons valued at $1,757,636, as compared with the figures shown in the preceding paragraph.

Output and Value.

In considering mineral production, the value of the crude material is used as far as practicable. Magnesite presents a peculiar example of a material which previous to 1916 was seldom handled on the market in the crude state. It is mainly calcined and ground before being considcred marketable. From 2 to 24 tons of crude material are mined to make one ton of the calcined. In the earlier reports an arbitrary value for the crude material at the mine was calculated from the above on the basis of the calcined value, there having been very little product shipped crude. On the contrary, however, considerable tonnages since 1916 have been shipped in the crude state, contracted for at prices ranging from $7 to $17 per ton, f. o. b. rail points. The average was $10.50 per ton, for 1922. This is the basis of the valuation used herein.

The production of crude magnesite in California during the year 1922 totaled 55,637 tons, valued at $594,665 f. o. b. rail-shipping point. This is an increase over the 47,837 tons and $511,102 in 1921.

The main hope for the future for California magnesite appears to be in the development of the plastic business, particularly in the territory west of the Rocky Mountains; and in the manufacture of refractory brick to be utilized mainly by the copper and lead smelters in the same district. It is possible that California magnesite may be sent via the Panama canal to the Atlantic seaboard; but, on account of our higher production costs, it is difficult to see how we can compete with the Grecian article at Atlantic ports.

Several plants are reported making refractory brick here from California magnesite. The ore from the White Rock Mine in Napa County, and that from the old Kolling (Refractory Magnesite Company) Mine, Sonoma County, is a natural ferro-magnesite and has found a ready market for refractory purposes.

In 1918, for the first time since Tulare County became an important producer of this mineral, it was surpassed in tonnage output for the year, but regained the lead in 1919, followed by Santa Clara and Napa Counties, respectively. The same ranking was retained in 1920; but Santa Clara took the lead in 1921. The largest individual producer in 1920-1922 has been the Western Magnesite Development Co., in Santa Clara County, operated under lease by C. S. Maltby. A total of 24,091 tons was reported as shipped calcined by Californian mines in 1922, representing anoroximately 52,205 tons of crude ore.

Owing to increased building operations, and the duty on foreign importations, the outlook for magnesite is improving. Research work is being conducted by the larger operators to insure uniformity of product, and to work out formulae and mixtures for its application in the plastic trade. Present quotations (March) are reported at $14 per ton crude, f. o. b. California points, and $40 per ton calcined.

Production of crude magnesite for 1922, by counties, is given in the following table, with total crude value:

Santa Clara

Stanislaus

Tulare

County

Fresno, Napa, San Benito, Tuolumne*.

Totals.

*Combined to conceal output of a single operator in each.

Total Magnesite Production of California.

The first commercial production of magnesite in California was made in the latter part of 1886 from the Cedar Mountain district,' southeast of Livermore, Alameda County. Shipments amounting to 'several tons' or 'several carloads' were sent by rail to New York; but there is apparently no exact record of the amount for that first year. The statistical records of the State Mining Bureau began with the year 1887, and the table herewith shows the figures for amount and value, annually, from that time. Shipments of magnesite from Napa County began in 1891 from the Snowflake Mine; from the Red Mountain deposits in Santa Clara County, in 1899; and from Tulare County in 1900.

Production of Magnesite In California, Since 1887.

'See U. S. Geol. Surv.; Mineral Resources of U. S., 1886, pp. 6 and 696.

Totals...

MICA.

Bibliography: State Mineralogist Reports II, IV. Bulletins 38. 67. No commercial production of mica has recently been reported in California. Production in previous years has been as follows:

"The different uses to which mica is put depend on its form-whether in sheets or in powder. Sheet mica is used in the electrical industry for glazing, and to some extent for other purposes. Ground mica is used chiefly in the decorative trades and in insulation.

"Sheet mica finds its greatest use in the electrical industry, where an insulating, noninflammable material is necessary. It is used in sheets and as washers and disks in dynamo-electric machinery, electric-light sockets, spark plugs, insulators, guards in rheostats, fuse boxes, and telephones. Flexible cloth and tape, covered with mica, find varied uses in electrical apparatus. Sheet mica is used for glazing the fronts of stoves and for making lamp chimneys and lamp shades. It is also used in spectacles, automobile shields, phonograph diaphragms, in windows where glass would be broken and in lantern transparencies.

"Ground mica is used for decoration in wall paper, to which it gives luster and brightness; in fancy paints, ornamental tiles, concrete, rubber goods, pipe and boiler Coverings, insulating compounds, fireproof paints and coverings, patent roofing material, molded mica (ground mica mixed with shellac), and calico printing; as absorbent for nitroglycerin in the manufacture of 'mica powder,' in tempering steel; to a large extent as a lubricant for wooden bearings, or, mixed with oil, as a lubricant for metal bearings; and as a filler for various products. Tar and other roofing papers are coated with coarsely ground mica to prevent sticking when they are rolled for shipment. A possible value of ground mica as a chemical source of potash salts is indicated in a recent Geological survey report.2

"It is understood that sheet mica has come to be of importance as a war mineral through its use abroad as windows in masks worn for defense against asphyxiating gases, and for other uses where a transparent, noninflammable, nonshattering material is necessary, as in automobile goggles and in windows for armored cars."

Present New York quotations for No. 1 quality sheet mica are from 15c per lb. for 1x2 inch to $3.60 per lb. for 6x6 inch, f. o. b. North Carolina, thumb trimmed; punch 8c, other grades, 25c to $3.25 according to size; flake 12c per lb.; scrap $25 per ton; f. o. b. Virginia points.

MOLYBDENUM.

Bibliography: Reports XIV, XVII. Bulletin 67. U. S. Bur. of Min., Bulletin 111. Proc. Colo. Sci. Soc., Vol. XI.

Molybdenum is used as an alloy constituent in the steel industry, and in certain forms of electrical apparatus. Included in the latter, is its successful substitution for platinum and platinum-iridium in electric contact-making and breaking devices. In alloys it is used similarly to and in conjunction with chromium, cobalt, iron, manganese, nickel, tungsten, and vanadium. The oxides and the ammonium salt have important chemical uses.

The two principal molybdenum minerals are: the sulphide, molybdenite; and wulfenite, lead molybdate; the former furnishing practically the entire commercial output. Molybdenite is found in or associated with acidic igneous rocks, such as granite and pegmatite. The chief commercial sources have been New South Wales, Queensland, and Norway, with some also from Canada.

Schaller. W. T.. Mica in 1916; U. S. Geol. Surv., Min. Res. of U. S. 1916, p. 304, 1917. Butler, B. S., Potash in certain copper and gold ores, with a note on muscovite by George Steiger; U. S. Geol. Survey Bull. 620, pp. 227-235, 1916.

Deposits of disseminated molybdenite are known in several localities in California, and in at least two places it occurs in small masses associated with copper sulphides. The only recorded commercial shipments of molybdenum ore in California were during the war, 1916-1918. Some development work has recently been done on a high-grade deposit at the head of the Kaweah River, Tulare County.

The 1917 output included some concentrates assaying up to 58% MOS, but the bulk of it was 1.5% ore which was shipped to Denver, Colorado, for concentration. That production came mainly from Shasta County, with smaller amounts from Inyo, Mono and San Diego counties. There were two concentrating plants built in California-one in each of the above first and last-named counties.

In the spring of 1918, a flotation plant operated for a short time by a lessee on the Boulder Creek mine, near Gibson Siding, Shasta County, made a small amount of 90% MoS, concentrate. The ore treated carried 2.6% MOS,. There has been none produced in California since 1918.

Present quotations for molybdenum ore are @ 65¢ per pound for 85% MOS, concentrates, plus duty.

The California production of molybdenum ore by years is summarized in the following tabulation:

Bibliography: Reports XIV, XVII. U. S. G. S., Bulletin 640-D. Nickel occurs in the Friday Copper Mine in the Julian District, San Diego County. The ore is a nickel-bearing pyrrhotite, with some associated chalcopyrite. Some ore has been mined in the course of development work, but not treated nor disposed of, as they were unable to get any smelter to handle it for them. Nickel ore has also been reported from other localities in California, but not yet confirmed. Present quotations for nickel are 25¢-30¢ per pound, according to grade and quantity.

MUSEUM.

The Museum of the State Mining Bureau possesses an exceptionally fine collection of rocks and minerals of both economic and academic value. It ranks among the first five of such collections located in North America; and contains not only one or more samples of most of the known minerals found in California, but many specimens from other states and foreign countries as well.

Mineral specimens suitable for exhibit purposes are solicited, and their donation will be appreciated by the State Mining Bureau as well as by those who utilize the facilities of the collection. The Bureau supplies a set of forty typical minerals and ores, appropriately labeled, for study purposes to any public school in the state upon

request. During the past 30 days, a total of 431 visitors signed their names to the Museum register, and in addition there are many others daily who fail to take note of our request for their signatures.

LABORATORY.

FRANK SANBORN, Mineral Technologist.

A total of 273 samples was received and determined during the thirty-day period covered by this report. From this number is appended a list having a possible commercial value, judging only from the samples submitted. The name and address of the sender of any of these samples will be sent upon request if the reference number is given. The eagerly active and partly successful attempts to exterminate the boll weevil in the cotton belts has resulted in many requests being made for the determination of arsenic, phosphates and potassium. The former is being used in preparing calcium arsenic to be used as an insecticide and the latter two in the making of fertilizers for use in the cotton fields.

15-37 Cobaltite (sulph-arsenide of cobalt).

15-38 Rutile (titanium oxide).

15-39 Allanite (contains didymium, yttrium, cerium, etc.).

15-40 Sericite-schist; also opal.