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The value of the total gem production in California annually since the beginning of commercial production is as follows:

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GRAPHITE. Bibliography: State Mineralogist Report XIII. Bulletin 67. Graphite has been produced from time to time in the state, coming principally from Sonoma County, and was used in paint manufacture. It is difficult for these deposits, which are not particularly pure, to compete with foreign supplies which go on the market almost directly as they come from the deposit.

The annual graphite production of the United States amounts to about $250,000; the yearly imports have a value of approximately two million dollars. These facts show the possibilities which are open to this branch of the mineral industry provided, of course, that investigation would show sufficient amounts of high grade material to compete with the imported article, which at the present time comes largely from Ceylon. Low grade ores are concentrated with considerable difficulty and the electric process of manufacturing artificial graphite from coal has been perfected to such a degree that only deposits of natural graphite of a superior quality can be exploited with any certainty of success.

On account of its unfusibility and resistance to the action of molten metals, graphite is very valuable. It is also largely used in the manufacture of electrical appliances, of “lead” pencils, as a lubricant and in many other ways. Amorphous or "lump” graphite, commonly carrying many impurities, is worth as low as $10 a ton. For some purposes, such as foundry facings, etc., the low grade material is very satisfactory. The price increases with the grade of the material until the best quality crystalline variety, ranges as high as $200 per ton.

Occurrence of graphite has been reported at various times from Calaveras, Fresno, Imperial, Los Angeles, Mendocino, San Bernardino,

San Diego, Siskiyou, Sonoma and Tuolumne counties. There is some prospect of a production for the current year from a property now being opened up in Los Angeles County.

During 1915 no production was reported in this state. The previous production, by years, was as follows:

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Totals

214,500

$6.185

GYPSUM. Bibliography: Bulletins 38, 67. Gypsum is widely distributed throughout the state, and is produced to a considerable extent, to supply the fertilizer manufacturers and the manufacturers of plaster and cement. One producer reports large orders for shipment during the current year to Honolulu, for fertilizer purposes.

During 1915, seven producers in Kern, Riverside and San Bernarding counties took out a total of 20,200 tons, valued at $48,953. The principal decrease from 1914 was due to the closing of the San Benito County quarries (formerly credited to Monterey).

Total annual production of gypsum in California since such records have been compiled by this Bureau is as follows:

Year

Tons

Value

Year

Tons

Value

1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902

2,700
2,500
3,000
3,000
2,000
2,000
1,620
2,446
5,158
1,310
2,203
3,100
3,663
2,522
3,875
10,200

$27,000 1903
25,000 1904
30,000 1905
30,000 1906
20,000 1907
20,000 1908
14,280 1909
24,584 1910
51,014 1911
12,580 1912
19,250 | 1913
23,600 1914
14,950 1915
10,088
38,750
53,500 Totals

6,914
8,350
12,850
21,000

8,900 34,600 30,700 45,294 31,457 37,529 47,100 29,734 20,200

$46,441 56,592 54,500 69,000 57,700 155,400 138,176 129,152 101,475 117,388 135,050 78,375 48,953

385,922

$1,602,798

INFUSORIAL EARTH.
Bibliography: State Mineralogist Reports II, XII, XIII. Bulle-

tins 38, 67. Infusorial, or diatomaceous, earth-sometimes called tripolite-is a very light and extremely porous, chalk-like material composed of pure silica (chalk, being calcareous) which has been laid down under water and consists of the remains of microscopical infusoria and diatoms. Its principal commercial use is as an absorbent; and it is also employed in the manufacture of scouring soap and polishing powders, and in making some classes of refractory brick. It is a first-class nonconductor of heat, where high temperatures are employed. In such cases, it is built in as an insulating layer in furnace walls.

The most important deposits in California thus far known are located in Monterey, Orange, San Luis Obispo, and Santa Barbara counties. It is also found in Fresno, Kern, Los Angeles, Plumas, San Benito, San Bernardino, Shasta, Sonoma, and Tehama counties.

During 1915, there were three actively operated quarries, in Monlerey, San Joaquin and Santa Barbara counties, which produced a total of 12,400 tons, valued at $62,000, compared with 12,800 tons, valued at $80,350, in 1914.

It will be noted that the average price varies widely from year to year. This fact is true in case of many of the industrial materials. The quality of the product fluctuates as does the demand; when both are favorable the maximum price obtains.

The first recorded production of this material in California occurred in 1889; total amount and value of output, to date, are as follows:

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1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903

$1,335 1904

1905
1906

1907
2,000 1908
2.040 1909

1910

1911 200 1912

6,950
3,000
2,430
2,531
2,950

500
1,813
2,191
4,129
8,615
12,810
12,400

$112,282

15,000 14,400 28,948 32,012

3,500 17,617 19,670 17.074 33,963 80,350 62,000

5

1913
1911
1915

422
2,703

2.532 16,015

Totals

63,682

$162,943

6—25437

LIMESTONE. Bibliography: State Mineralogist Reports IV, XII. Bulletin 38. Limestone was produced in 10 counties during 1915, to the amount of 146,324 tons, valued at $156,288. This amount does not include the limestone used in the manufacture of cement nor of lime for building purposes, but accounts for that utilized as a smelter flux, for sugar making, and in other chemical and manufacturing processes (including fertilizers, roofing preparations, whiting for paint, terrazzo and for CO2). The marked drop in the 1915 output as compared with the 1914 figures, is due in part to our transferring to the macadam classification a large tonnage of limestone employed as road metal; but which in the 1914 report was classified as “industrial" limestone.

Distribution of the 1915 output is as follows:

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In the early reports of this Bureau values for lime and limestone were not segregated. The following tabulation showg the total combined value of such material since records for the state were first compiled, in 1887, to date:

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LITHIA. Bibliography: State Mineralogist Reports II, IV. Bulletins 38, 67. Lithia mica, lepidolite (a silicate of lithium et al.) utilized in the manufacture of artificial mineral water, fireworks, etc., was mined and sold in San Diego County during the years 1899–1905 inclusive, but there has been no commercial production since the latter date, until 1915. Some ambygonite, a lithium phosphate, has also been obtained, from pockets associated with the gem tourmalines. In 1915, the yield of lepidolite was 91 tons, valued at $1,365.

The following table of analyses shows the composition of some of the lithia minerals:

Analyses of Lithia Minerals. 10

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Lithia mica total production in the state has been as follows:

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

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Totals

150

$9,300

10 Bulletin No. 38, p. 308.

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