Chalcedony, Chlorite and Amethyst

Chalcedony, Chlorite and Amethyst

ID	659
Mineral	Chalcedony Chlorite Amethyst
Location	Soledade - Rio Grande do Sul - Brazil
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Chalcedony information at mindat.org View Chlorite information at mindat.org View Amethyst information at mindat.org

Mindat data

ID	960
Long ID	1:1:960:9
Variety of	3337
Entry type	2
Other Occurrences	Very common. As nodules, vein fillings, crusts in volcanic rocks. As sinter-like crusts in low- to medium temperature hydrothermal veins. Main constituent in silica-rich marine sedimentary rocks. As nodular concretions and layers in limestones and marls. As a metasomatic replacement in limestones and marls ("replacement chert"). As cement in sandstones. Replacing other minerals in pseudomorphoses. As a fossilizing material (petrified wood, coral agate).
Diapheny	Translucent
Tenacity	brittle
Colour	colorless, white, gray, blue, any color due to embedded minerals, multicolored specimen not uncommon.
Hardness (min)	6.5
Hardness (max)	7.0
About the name	Mentioned by Agricola (1546) of a stone named for the town of Chalcedon, now called Kadıköy, and is a district within the city of Istanbul, Turkey.
Streak	White
Cleavage Type	None Observed
Fracture type	Conchoidal,Sub-Conchoidal
Twinning	Quartz crystallites in the chalcedony fibers are polysynthetically twinned by the Brazil law (left- and right-handed domains).
UV	None in a pure specimen, however, green fluorescence in short-wave UV light is very common at many localities.
Comment Luster	vitreous when polished, fractured surfaces have a dull or waxy luster

ID	1016
Long ID	1:1:1016:6
Entry type	5
Diapheny	Translucent,Opaque
Colour	Green to black
Hardness (min)	2.0
Hardness (max)	3.0
About the name	From the Greek chloros (χλωρός), meaning "green", in reference to its color.
Streak	Colorless to pale green
Crystal System	Monoclinic
Cleavage Type	Perfect
shortcode_ima	Chl

ID	198
Long ID	1:1:198:0
Variety of	3337
Entry type	2
Other Occurrences	Very common, in many different environments. The commercially most important occurrences are in volcanic rocks, where amethyst crystals outline former gas cavities. In low and medium temperature hydrothermal veins associated with iron ores. As late overgrowth ("scepter quartz") on quartz in pegmatite and alpine-type environments.
Colour	Violet - purple
Lustre	Vitreous
About the name	From Greek "a-methystos", meaning "not drunk". In ancient times, it was believed that amethyst warded off drunkenness. Drinking cups were sometimes carved from amethyst. At the same time, the colour of the red wine drunk from these cups is said to have been approximately the same colour as the cups. Therefore, the wine could be diluted with water without the drinker noticing, thinking it was the material of the cup itself that warded off drunkenness.

Price: € 100

Dimensions: None mm x None mm x None mm

Weight: Not registered

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Symbol	Element
O	Oxygen
Si	Silicium