|MAGNETITE MINERAL FACTS|
|The Gem and Mineral Collector's Photo Gallery by Nevada Outback|
Magnetite Mineral Facts:
Chemical Formula: Fe3O4
Colors: Black and streak is black as well.
Cleavage: No cleavage, magnetite breaks with an uneven choncoidal fracture.
Luster:. weak metallic or sub-metallic luster.
Optics: (Refractive Index): Opaque
Structure and Associated Minerals:
It occurs also as little grains among the decomposition products of iron-bearing silicates, such as olivine and hornblende. The larger masses are either segregations from igneous magmas or deposits from hot solutions and gases emanating from them. The mineral weathers to limonite and hematite and occasionally to the carbonate, siderite.
As " black sands," magnetite occurs in placer deposits, as in the Yukon and Columbia rivers. Most placer gold deposits contain significant magnetic black sand. Most large deposits of magnetite occur as segregations in igneous rocks, chiefly in the more basic rocks, gabbros, norites and sometimes syenites, as at Taberg and Kiruna, in Sweden, at the Adirondacks in the United States, and in the Urals. Magnetite also occurs as lenticular bands, interfoliated with schists, as in Scandinavia, Urals, California, Saxony, etc.
Identification and Diagnostics
Magnetite, Magnetic black Sand
Localities and Origins:
The localities at which magnetite has been found are so numerous that only those of the greatest economic importancemay be mentioned here. In the United States large lenses occur in the limestones and siliceous crystalline schists in the Adirondacks, in Warren, Essex and Clinton counties of northern New York; and in the schists and granitic rocks of the Highlands in New Jersey; and at Cornwall, Pennsylvania and at at Magnet Cove, Arkansas. Important foreign localities are in Norway and Sweden, where great segregated deposits are worked as the chief sources of iron ore in these countries. Magnetite occurs in Devonshire, Cornwall, and other localities in England, also in many places in Scotland and Ireland, and indeed in most parts of the world. Natural magnets or lodestones are found in Siberia and in the Harz Mountains of Germany. The magnetite is separated from the rock with which it occurs by crushing and exposing to the action of an electro-magnet.
Return to the Mineral Collectors Information Page
Please note that the author, Chris Ralph, retains all copyrights to this entire document and it may not be reproduced, quoted or copied without permission.
NEVADA OUTBACK GEMS TURQUOISE AND JEWELRY
Nevada Outback Gems
|Find out more by checking out All of our links below:|
|View our Contemporary Turquoise Jewelry - Wearable Artwork!||View our Unique Gem Quality Turquoise Cabochons|
|Premium Jewelry, with Gemstones of all types||Top Quality Loose Gemstones - Gemstones of all types|
|Rare Crystals and Gemstone Rough, all types||Our Free Colored Gemstone Information Encyclopedia|
|Chris' Gold Prospecting Encyclopedia||Take a virtual tour of our Nevada Turquoise mines|
|Miners Reference Pages||California Gold Rush Stories||More Info about Turquoise, the Beautiful Gem|
|Metal Detecting with the MXT Metal Detector||Nevada Outback Gems Homepage|
|Build Your Own Mining Equipment||Investing in Gold and Precious Metals|
|Basic Placer Mining||More information about us - Nevada Outback Gems|
|Locations to Prospect for Gold||The Rockhound's Corner||Nevada Outback Library and Bookstore - Learn more!|
|Chris's Prospecting Adventures||About Nevada Turquoise||More Info about Gem Cutting||Tanzanite Jewelry|
|Nevada Outback Gems Site Map||Make Your Own Jewelry||Buy Safely on EBay: avoid fraud and scam artists|