Saturday, February 28, 2009
Probably one the most fascinating mineral combinations there is (according to me), hematite and amorphus silica (quartz). I'd say this is the equivalent to an opal, only the iridiscense is not because of water molecules, but because of the iron oxide embedded in the silica. First time I saw one of these specimens - common in Aguascalientes, Mexico - was in college in my Mineralogy class back in 1975 (Faculty of Engineering of the National Autonomous University of Mexico), and I fell off my chair, I was in shock with the beauty of this baby.
Anyhow, I am not sure why this mineral has never made it to precious stone status, but if I ever become president of the Mexico, I'll declare it the stone of the country. If you don't like it as much as I do, don't vote for me.
Ok, let us see what are the fire agate (another form of quartz) life technical specifications:
Chemical Formula: SiO2
Environment: Sedimentary, metamorphic, and igneous rocks.
Locality: Very common mineral found world wide.
Name Origin: From the German "quarz", of uncertain origin according to many, however I heard once that it comes from the old saxonic that means ice very frozen.
Synonyms of quartz:
Agate - banded variety of chaledony
Amethyst - purple
Avanturine - feebly translucent chalcedony
Carnelian - flesh red chalcedony
Cat's Eye - chatoyant
Chalcedony - microcrystalline quartz
Chert - cryptocrystalline quartz
Chrysoprase - apple green chalcedony
Citrine - yellow
Flint - microcrystalline quartz
Hornstone - flint
Jasper - red or brown chalcedony
Moss Agate - variety of chaledony
Plasma - green chalcedony
Prase - leek green chalcedony
Rose Quartz - rose colored
Sapphire Quartz - blue colored
Smoky Quartz - brown to black
Tiger Eye - pseudomorph of asbestos
Cleavage:  Indistinct
Color: Brown, Colorless, Violet, Gray, Yellow.
Density: 2.6 - 2.65, Average = 2.62
Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Habits: Crystalline - Coarse - Occurs as well-formed coarse sized crystals.
Crystalline - Fine - Occurs as well-formed fine sized crystals.
Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.
Hardness: 7 - Quartz
Luster: Vitreous (Glassy)
I hope you enjoy a terrific weekend, today is 2/28/09, visit my website if you have some chance: Oscar el Mexicano