Hardystonite
Encyclopedia
Hardystonite is a rare calcium zinc silicate mineral
first described from the Franklin, New Jersey
, USA
zinc
deposits. It often contains lead
, which was detrimental to the zinc smelting process, so it was not a useful ore mineral. Like many of the famous Franklin minerals, hardystonite responds to short wave ultraviolet (254 nm wavelength) light, emitting a fluorescence from dark purple to bright violet blue. In daylight, it is white to gray to light pink in color, sometimes with a vitreous or greasy luster. It is very rarely found as well formed crystals, and these are usually rectangular in appearance and rock-locked.
Hardystonite has a chemical composition of Ca2ZnSi2O7. It is frequently found with willemite
(fluoresces green), calcite
(fluoresces red), and clinohedrite
(fluoresces orange). Hardystonite can be found altered to clinohedrite
CaZn(SiO4)·H2O through direct hydrothermal alteration.
Other minerals often associated with hardystonite are franklinite
, diopside
, andradite garnet, and esperite
(fluoresces yellow).
It was first described in 1899 by J.E. Wolff, when the New Jersey Zinc Company
mines were located in what was called Franklin Furnace
, in Hardyston Township, New Jersey.
Silicate minerals
The silicate minerals make up the largest and most important class of rock-forming minerals, constituting approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group...
first described from the Franklin, New Jersey
Franklin, New Jersey
Franklin is a Borough in Sussex County, New Jersey, United States. As of the 2010 United States Census, the borough population was 5,045.Franklin, known as the "Fluorescent Mineral Capital of the World," is located over a rich ore body containing more than 150 minerals, many of them fluorescent and...
, USA
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
deposits. It often contains lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, which was detrimental to the zinc smelting process, so it was not a useful ore mineral. Like many of the famous Franklin minerals, hardystonite responds to short wave ultraviolet (254 nm wavelength) light, emitting a fluorescence from dark purple to bright violet blue. In daylight, it is white to gray to light pink in color, sometimes with a vitreous or greasy luster. It is very rarely found as well formed crystals, and these are usually rectangular in appearance and rock-locked.
Hardystonite has a chemical composition of Ca2ZnSi2O7. It is frequently found with willemite
Willemite
Willemite is a zinc silicate mineral and a minor ore of zinc. It is highly fluorescent under shortwave ultraviolet light.It occurs in all different colors in daylight, in fibrous masses, solid brown masses , and apple green gemmy masses.It was discovered in 1830 and named after William I of the...
(fluoresces green), calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
(fluoresces red), and clinohedrite
Clinohedrite
Clinohedrite is a rare silicate mineral. Its chemical composition is a hydrous calcium-zinc silicate; CaZn4·H2O. It crystallizes in the monoclinic system and typically occurs as veinlets and fracture coatings. It is commonly colorless, white to pale amethyst in color. It has perfect cleavage and...
(fluoresces orange). Hardystonite can be found altered to clinohedrite
Clinohedrite
Clinohedrite is a rare silicate mineral. Its chemical composition is a hydrous calcium-zinc silicate; CaZn4·H2O. It crystallizes in the monoclinic system and typically occurs as veinlets and fracture coatings. It is commonly colorless, white to pale amethyst in color. It has perfect cleavage and...
CaZn(SiO4)·H2O through direct hydrothermal alteration.
Other minerals often associated with hardystonite are franklinite
Franklinite
Franklinite is a mineral with formula ZnFe2O4. It is associated with the Franklin Mine and Sterling Hill Mines in New Jersey.-See also:* Spinel* Classification of minerals* List of minerals-References:*...
, diopside
Diopside
Diopside is a monoclinic pyroxene mineral with composition MgCaSi2O6. It forms complete solid solution series with hedenbergite and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class...
, andradite garnet, and esperite
Esperite
Esperite is a rare complex calcium lead zinc silicate related to beryllonite and trimerite that used to be called calcium larsenite...
(fluoresces yellow).
It was first described in 1899 by J.E. Wolff, when the New Jersey Zinc Company
New Jersey Zinc Company
The Horsehead Corporation , formerly the New Jersey Zinc Company, is an American producer of zinc and related materials.The New Jersey Zinc Company was for many years the largest producer of zinc and zinc products in the United States. The company thrived in the period from 1897 to 1966, at which...
mines were located in what was called Franklin Furnace
Franklin Furnace
Franklin Furnace, also known as the Franklin Mine, is a famous mineral location for rare zinc, iron, manganese minerals in old mines in Franklin, New Jersey, USA. This locale produced more species of minerals and more different fluorescent minerals than any other location...
, in Hardyston Township, New Jersey.