Santa Clarita Valley History In Pictures

The Pacific Mineralogist, December 1941.
Includes: Minerals of Mint Canyon.

Minerals of Mint Canyon (Excerpt).

Pyrite. Auriferous (gold bearing) Iron sulfides. "Fool's Gold." Axiom of mineralogy: "Wherever there's pyrite there's gold." Every iron stained specimen worth an assay.

Quartz XLS. Large or distinct quartz crystals in cores of agate geodes. Solid quartz cores and hollow cored geodes covered with fine scintillating xl coating. Silica or indistinctly fine or micro-xl quartz in the bull quartz matrix of the iron pyrite ore from Governor mine. Many specimens disintegrated to "sugar" quartz. Pure silica or quartz as clear as a window pane may be a valuable gold-bearing ore yielding high values in invisible free flour and flake gold or grayed with silver. Large deposits of silica are valuable and in demand on West Coast for glass manufacturing.

Ribbon Agate Geode Gemstones. The ribbon agate geode deposits visited are among the finest in the country. Solid geodes are called nodules and are exceptionally fine cutting material yielding settings in a variety of shades of cobalt blue and white. The silica is deposited by cooling mineral waters from great depths, bearing different stains for different periods of time, forming rings from outside in. If deposition closes passage flow, balance of silica deposit will be in form of quartz xls, filling or partially filling cavity. Nodules of solid banded agate are formed on underside of geodes, or a portion of the geode will show bedding planes of seasonal or periodic deposit. Process may take only a few months or a number of years. It is the same process that goes on when agate replaces wood or other cellulose or soluble minerals. Geodes are thought to be formed in gas voids in basalt deposits. Basalt is formed on the surface then buried to depths where underground mineral waters fill voids with agate and quartz silica deposits, then brought to the surface again by later earth deformations. Basalt weathers away and decomposes, leaving geodes. Basalt with agate filled voids is to be found in this location. The small agate nodules coated with green griffithite noted later.

Selenite. White gypsum mineral formed in file faced flats and planar cleavage xls.

Jasper. Some few fragments of jasper of gem quality may be found; red moss predominates.

Bloodstone. Some very fine pieces of dense green, red flecked bloodstone of gem cutting quality are in the vicinity. A sample of what to look for should be on hand.

Moss Agate Gemstone. Very high quality green (copper oxide) moss agate, red (iron oxide or limonite moss), and black moss agate (fine fernlike xline deposits of manganese dioxide in silicon dioxide) are to be found. The latter are very scarce but well worth the hunt. Iron agates shade into fine red moss jaspers that are beautiful in the extreme. Green copper stained agate is plentiful, but usually too dense to class as moss agate. Careful chipping and selection yields fine small gemstones. A ledge of fine quality moss agate ten inches thick was found on one trip.

Griffithite. Green cuprous coating on agate nodular deposits in basalt voids.

Copper Stained Quartz. This is a mineral specimen of itself, showing copper oxide coatings. The material verges into a close approach to Californite and Chrysocolla.

California Opal. A type of hydrous silicate having a greater amount of water of crystallization and having an opalescent but opaque white glassy appearance. It is not gem material but is possible genuine opal in a state of dehydration and decomposition. Genuine gem opals are to be found in this area, of fine luster and color, which are not from Paradise Valley, California, or Lightning Ridge, Australia. The disintegrated opal will fluoresce and phosphoresce, and may be spotted by ultra violet light in night prospecting.

Colemanite Borax. Fine specimens of borax but with earthy impurities in most instances are to be found. Single and massive or stratic deposit materials are available in generous quantities.

Howlite Gemstone. Finest quality howlite or "cauliflower ore," a very dense grayish white mineral with gray streaks in crystalline surface junctures is to be found in single pieces of sufficient size to cut bookends. Single specimens of good quality are still available, but the location is rapidly disappearing or being picked out.

Mesozoic Schist. Oldest rock outcropping in western half of the United States. Of outstanding geological significance. End point in metamorphosis or change of mineralogical formation.

Mica Schist. Schist of a more recent origin and having fine silver sheen. Being mined for flagstone due to weathering and ready cleavage into thin sections.

Graphitic Schist. Graphite and kaolin bearing schist, very dark and slick but with so low a graphite content as to be of no commercial significance. There has been a recent graphite claim located near Pacoima Dam.

Hematite Coated Pebbles. Mineral specimens of fine polished quartz pebbles having a high polishable coating of hematite, or magnetite. Red hematite Fe2O3 surrounding the pebbles, which are coated with metallic lustered magnetite, an iron oxide of another valence of iron, Fe3O4, which is attracted by a magnet and may possess magnetic properties and is known as lodestone.

Hematite Boulders Bearing Gallium. Hematite boulders deposited by the Los Angeles river, in its old bed are to be found. They are almost pure hematite, metallic of shiny stove lid appearance of crystalline structure, and containing 2/100% gallium, a rare metal of value several times that of gold. These boulders are being mined on top of Mount Baldy in what was once the old river bed.

Pegmatite. White quartz of feldspathic granite known as the mother of gems and minerals exuded in dikes from cooling magmas after they have broken out of the casement formed of minerals, solidifying at higher temperatures. The metals and minerals held in solution by aqueous igneous fusion at profound depths beneath the earth's surface, are extruded by the enormous forces of compression of the solidifying outer layers, and when they solidify are separated. The pegmatite identifies or locates the zone of change, and the trained mineralogist knows that where he finds pegmatite, he may expect to find any other precious metallic minerals which were contained in the magma, also crystallized out in a pure or isolated state. Pegmatite marks the spot to look. Fine granitic pegmatites are to be found on Angeles Crest Highway cutoff, and below Pacoima dam. The world-famous Pala mines in San Diego County are located in pegmatite veins, which were originally worked for their metallic contents in gold and silver.

Titanite. Titanium ores are to be found in the area. Many claims are held by the DuPont Company. Titanium Oxide is used to give paint sunlight resisting properties.

LW3518: pdf of original periodical purchased 2018 by Leon Worden. Download individual pages here.


Copper Hill Mining Co. Stock Cert 1863


Occidental Copper Mining Co. Stock Cert 1863


• Minerals of Mint Canyon (Pacific Mineralogist 12/1941)


1966 Rockhounding Guide


• Rockhouding Story 1957


Loading Chute


Gemstone Map


Copper Vein


Mine Shaft

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