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The Rock Professor has provided you with a mineral
information card. Print on stock paper, and cut out to
enhance your rock and mineral products.
To print: with your cursor, highlight the entire card below,
right click and select print, then click on "selection"
and print.
| THE ROCK PROFESSOR |
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Image of Amethyst Cathedrals in a Brazilian warehouse
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AMETHYST & CITRINE CATHEDRALS
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The cathedrals on our Website are true wonders of nature - they come from a series of basaltic flows in the southern Brazilian state of Rio Grande do Sul. They are mined by hard rock mining methods, then cleaned cut and polished by local craftsmen.
Cathedrals are large GEODES formed in large gas bubbles in basaltic lava.
Cathedrals are graded for sale by exterior size and shape; crystal size, color and perfection; and overall appearance. Also, the appearance of other minerals such as calcite and quartz which form after the amethyst, may add to the value.
Go to these Rock Professor pages for more information on AMETHYST or CITRINE.
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Amethyst: Chemistry: SiO2 ♦ Variety: Quartz ♦ Transparency: Transparent to translucent ♦ Luster: vitreous ♦ Crystal system: Trigonal ♦ Moh's hardness: 7 ♦
Color: Various shades of purple ♦ Localities: Southern Brazil and Uruguay.
Citrine: A yellowish-brown variety of quartz often formed by heating amethyst
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