*Production of Ætna and Napa Con, not segregated in former years.

CLAY—see Kaolinite.
COAL-See Lignite.

COBALT see Erythrite and Millerite.
COBALT BLOOM-see Erythrite.

41. COCCINITE. Iodide of mercury.

Locality given by Dana, San Emidio Cañon, Kern County.
COLEMANITE-
E-see Priceite.

42. COPPER. Copper in the metallic state has not been found in any considerable quantity in California. The following are the known localities:

Calaveras County. Found sparingly in the Keystone, Napoleon, Lancha Plana, and Union Mines. The Satellite Mine, the Lancha Plana under a new name, has produced a fine lot of specimens which were exhibited by Horace D. Randlett at a late exhibition of the Mechanics' Institute at San Francisco.

Del Norte County. With cuprite, Pearl Mine.

Napa County. Near St. Helena.

Nevada County. Meadow Lake, with cuprite.

Plumas County. At Mumford's Hill, with rhodonite.

Sacramento County. Cosumnes Mine.

San Luis Obispo County. Pieces of float copper have been found in the Coast Range, sometimes associated with cuprite; one mass weighed 37.3 pounds.

Santa Barbara County. In grains in serpentine rocks (Blake).
Shasta County. Cow Creek and Iron Mountain.
Trinity County. With cuprite.

43. COPPERAS. Coquimbite in part, hydrous sulphate of iron, occurs in several localities in the State, and is generally the result of solfataric action, as at the Sulphur Bank, in Lake County, where it is very abundant. No analysis has been made of it, so that its exact composition is unknown. Dr. Trask, in his report of 1854, fol. 56, says it is found in large quantities near the town of Santa Cruz, in such quantity that it could be extensively manufactured as an article of commerce. I formed the same opinion as to the Sulphur Bank before mentioned. A sample of saturated solution of sulphate of iron was sent to the Mining Bureau recently, leached from ground sulphurets that the party who sent it states could be obtained at the rate of seventy gallons per ton. This is only another evidence of the enormous waste that is permitted in the metallurgy of ores in California. COPPER-Blue Carbonate-see Azurite.

COPPER GLANCE-see Chalcosite.

COPPER-Green Carbonate-see Malachite.

44. CORUNDUM. According to Baron Richthoven it is found in the drift in the San Francisquito Pass, Los Angeles County.

45. CUBAN. Sulphide of copper and iron. It is said to be found on Santa Rosa Creek, San Luis Obispo County. One mass weighed 1,000 pounds. I consider this statement as doubtful.

46. CUPRITE. Red oxide of copper. Cuprite is rather a common mineral in California. The following are the most important localities: Colusa County. Candace Mine.

Del Norte County Pearl Copper Mine, with native copper.
Kern County. San Emedio Ranch, with malachite.

Mono County. Kerrick Mine, with azurite, malachite, partzite, and native silver.

At Lundy, in microscopic crystals, with cerargyrite and chrysocolla. On the borders of Mono Lake and at Mammoth.

Napa County. Near St. Helena, in masses of considerable size, with native copper.

Nevada County. At Meadow Lake, with native copper.

Placer County.

Plumas County.

Near Lincoln.
Reward Mine.

Shasta County. Peck Mine, Copper Hill, in microscopic crystals.
Trinity County. With native copper, exact locality unknown.
Tulare County. May Flower Mine, Mineral King District.

And at numerous localities in the Inyo Mountains, Mono, and Inyo Counties.

According to Blake, it occurs sparingly in thin crusts and sheets with the surface ores of the principal copper mines in Calaveras County, especially the Union and the Keystone; in Mariposa County, at La Victoire Mine, with green and blue carbonates of copper; in Del Norte County, at the Evoca, Alta, and other mines, in very good cabinet specimens, the cavities being lined with crystal; in Plumas County, and in the upper parts of most of the copper veins of the State.

47. CUPROSCHEELITE. Tungstate of lime and copper. This new and interesting mineral was first found in California in the Green Monster Copper Mine, in Kern County, about twelve miles east of White River Post Office. It is generally associated with black tormaline. A large crystal was found at this locality, which is the only one of this mineral known. In 1879 a fine specimen was sent to San Francisco from Fresno County, but the exact locality was not given.

48. DATOLITE, OR DATHOLITE. This mineral has, as yet, been found at one locality only, but from the universal distribution of boracic acid in the State, it is likely to be found elsewhere. The locality is a mining tunnel near San Carlos, Inyo County. It occurs with grossularite in fine crystals, the datholite being the matrix in which the grossularite is embedded. This mineral was first noticed by the late J. Lawrence Smith, and an account of it published in the American Journal of Science a number of years ago

This

49. DIALLOGITE. Rhodochrosite, carbonate of manganese. mineral is represented in the State Museum by a single specimen, No. 3584, in beautiful pink crystals, from the Colorado Mine, No. 2, Monitor District, Alpine County.

50. DIAMOND. For the details of the occurrence of diamonds in California, and of general history, the reader is referred to the fourth annual report of this office, folio 157. The following are the known localities in the State:

Amador County. A very interesting stone was found in July, 1883, by George Evans, on the surface of the ground at Rancheria, a small mining camp, about four miles northwest of Volcano. It weighs about 255 milligrams. Its length is 0.315 inches; thickness, 0.215 inches. It is irregularly globular in form, all the faces being convex. It is pale straw colored, very

brilliant, and, as far as can be distinguished even under the microscope, is without a flaw. Jackass Gulch, near Volcano, and Indian Gulch, Gopher Hill, near Fiddletown, and other localities. Diamonds have been found at Volcano in a peculiar volcanic formation, described by Professor Whitney as "ashes and pumice cemented and stratified by water." The crystals had the form of the icositetrahedron, with faces curved in the manner peculiar to the diamond.

Butte County. A fine crystal was found some years ago in the west branch of Feather River. It was about four millimeters in diameter. It was afterwards lost. A number of diamonds have been found at Yankee Hill, but the exact number is not known.

A fine diamond from the Spring Valley Mine, Cherokee, has been presented to the State Museum, No. 4033, by Mr. G. F. Williams, Superintendent. Mrs. Harris has a beautiful Cherokee rough diamond set in a ring. Mr. Harris, who was formerly Superintendent of the Spring Valley Hydraulic Mine, has another, which has been cut. Of the two, I consider the natural crystal the most interesting and beautiful. Mrs. W. C. Hendricks of Morris Ravine, near Oroville, also has a fine Cherokee diamond set in a ring.

In August of 1883 I visited Cherokee, Butte County, specially to study that celebrated diamond locality. Mr. A. McDermott, druggist of Oroville, says that a diamond was sent to him in 1862 which was as large as a small pea. It was nearly globular and obscurely crystallized and of yellow color. He does not know the subsequent history of the stone, where it was found, or the owner's name.

At Cherokee, diamonds and zircons are found in cleaning up sluices and undercurrents. The first notice of diamonds at this locality dates from 1853, the largest discovered, which was two and a quarter carats (nine grains), is now in the possession of John More. There have been from fifty to sixty found, from first to last; some were rose colored, some yellow, others pure white, and all associated with zircons, platinum, iridium, magnetite, gold, and other minerals.

El Dorado County. Mr. W. A. Goodyear is quoted in Whitney's "Auriferous Gravels of the Sierra Nevada of California" as follows: "He saw a diamond in the possession of Mrs. Olmstead, at Dirty Flat, near Placerville, which measured nine thirty-seconds of an inch maximum diameter, and weighed one and a quarter carats-561 grains. It was found by Mr. Olmstead in cleaning up the sluices of the Cruson tunnel, Dirty Flat.

At the McConnell & Reed claim, on the south side of Webber Hill, a diamond the size of a small white bean was found. This diamond was discovered a few feet above the bedrock. Mr. McConnell thinks on a previous occasion he had thrown away a diamond as large as the end of his thumb, in ignorance of its true character. Two other diamonds were found in another claim, also on the south side of Webber Hill.

Three or four diamonds were found near White Rock. Mr. Goodyear purchased a crystal of Mr. Thomas Potts. It weighed half a carat-two grains; had a slight yellowish tinge, and was found in washing the gravel which came from a tunnel driven into White Rock. Near the same locality three diamonds were found in gravel by the Wood Brothers, in 1867. The largest was valued by a San Francisco dealer at fifty dollars.

An interesting letter from Placerville to the State Mineralogist, from W. P. Carpender, gives much information on this subject. It is published in full in the fourth annual report, folio 169.

Nevada County. French Gulch-one crystal weighed 74 grains.

Trinity County. An examination of the platinum sands of the Trinity

River was made by Professor F. Woehler, of Gottingen, who found diamonds in them. After removing gold, platinum, chromic iron, silica, rhuthenium, etc., by the usual methods, he examined the residue microscopically, and observed colorless, transparent grains, which he presumed to be diamonds. Subsequent combustion in oxygen and precipitation from solution of baryta, by the carbonic acid evolved, convinced him that the microscopic crystals were true diamonds.

DIATOMACEOUS EARTH-See Quartz.

51. DOLOMITE. Carbonate of lime and magnesia. Inyo marble. Dolomite is rather abundant in California. The following are the most important localities at present known:

Amador County. In narrow, snow-white veins, traversing talcose and chlorite rock bearing coarse, free gold. (Blake.)

Calaveras County. In the Winter, Hill's, and other mines, with quartz and free gold, sometimes in cavities, in fine crystals. (Blake.)

Inyo County. Dolomite is very abundant in the Inyo range of mountains, from White Mountain to Coso, and in very large deposits. The White Mountain Peak is named from its white appearance. The summit, which seems to be of this rock, is often supposed to be covered with snow, when it Attention has lately been called to the white variety of this marble, which resembles the finest Carrara marble, from which the name "Inyo marble" has been taken. A technical description of this dolomite marble has been given under the head of Building Stones.

Los Angeles County. Tejunga Cañon, San Gabriel Mountains.
Mendocino County. Exact locality unknown.

Napa County. Mount Catherine.

Plumas County. With pyrite at Mumford's Hill.

San Bernardino County. In the Armagosa Mines, with free gold; also in the wash of the Armagosa River, in white bowlders, which, broken, resemble the finest Italian marble.

San Luis Obispo County. At Morro, in nodules resembling fossil coral; from less than an inch to several feet in diameter. Some have cavities lined with crystal.

52. DUFRENOYSITE. A mineral composed of sulphur, arsenic, and lead. Said to be found in the Union Mine, Cerro Gordo, Inyo County (doubtful).

ELECTRUM-see Gold.

53. EMBOLITE. Chloro-bromide of silver. It is rather an abundant mineral in southern California, but is seldom found in masses of any considerable size, being generally disseminated throughout the other ores of silver, or occurring in crusts. It is almost always associated with cerargyrite, for which it is often mistaken. It is found in the Minnie Mine, Sweetwater Range, Mono County, and in the Indiana Mine, near Swansea, Inyo County. A large specimen of silver ore in the State Museum (brecciated), a large portion of which is covered with embolite, is from the Alhambra Mine, Calico District, San Bernardino County. EMERALD NICKEL-See Zaratite.

54. ENARGITE. Sulpho-arsenide of copper, sometimes containing antimony, iron, silver, or zinc. It occurs at least at one place in California, where it is abundant, associated with pyrite and other minerals. It has a disposition to change to arsenious acid and sulphate of copper, a reference