Szenicsite is a copper hydroxy

molybdate In chemistry a molybdate is a compound containing an oxoanion with molybdenum in its highest oxidation state of 6. Molybdenum can form a very large range of such oxoanions which can be discrete structures or polymeric extended structures, althou ...

mineral, named after husband and wife Terry and Marissa Szenics, American

mineral collector Mineral collecting is the hobby of systematically collecting, identifying and displaying mineral specimens. Mineral collecting can also be a part of the profession of mineralogy and allied geologic specialties. Individual collectors often sp ...

s who found the first specimens. When it was first discovered in Atacama, Chile, it was thought to be lindgrenite. The occurrence appeared in an isolated area, which was about one cubic meter in size. The mineral occurred in cavities of copper bearing

powellite Powellite is a calcium molybdate mineral with formula CaMoO4. Powellite crystallizes with tetragonal - dipyramidal crystal structure as transparent adamantine blue, greenish brown, yellow to grey typically anhedral forms. It exhibits distinct cle ...

and matrix rich

molybdenite Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum ato ...

. These cavities were filled with a material resembling clay. Outside of the zone the szenicsite crystals grew, copper levels seemed to decrease, and the mineralization changed to lindgrenite. Moving further from the zone, the minerals growing seemed to be lacking copper, and consisted of powellite blebs in the ore. Szenicsite was approved by the IMA in 1993.

Properties

Szenicsite is a dimorph of markascherite. This mineral is

pleochroic Pleochroism (from Greek πλέων, ''pléōn'', "more" and χρῶμα, ''khrôma'', "color") is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light. Backgroun ...

, which is an optical phenomenon, meaning that depending on the axis it is being inspected on, it changes colors. When viewed on the X axis, the mineral can be seen as yellow-green, while if inspected on the Y and Z axes, it appears green. Szenicsite consists of copper (45.54%), oxygen (22.92%), molybdenum (22.92%), and further has a negligible, 0.96% hydrogen in its composition. This mineral grows bladed radial crystals. These crystals are thin and lath-like, and form aggregates. They grow from a central point, without creating stellar shapes. Szenicsite does not show any radioactive properties. During an experiment carried out by four Russian mineralogists, it was found out that when heated up to above 350°C, szenicsite decomposes to cupromolybdite and

tenorite Tenorite is a copper oxide mineral with the chemical formula CuO. Occurrence Tenorite occurs in the weathered or oxidized zone associated with deeper primary copper sulfide orebodies. Tenorite commonly occurs with chrysocolla and the copper c ...

according to the reaction: 2Cu₃(MoO₄)(OH)₄ → Cu₃O(MoO₄)₂ + 3CuO + 2H₂↑.

Occurrences and localities

Szenicsite is an uncommon

secondary mineral A primary mineral is any mineral formed during the original crystallization of the host igneous primary rock and includes the essential mineral(s) used to classify the rock along with any accessory minerals. In ore deposit geology, hypogene processe ...

that grows in the oxidized zone. Szenicsite is a type locality at the Jardinera No. 1 Mine, at Chile. By error, the type locality was previously given as "Tierra Amarilla". The mineral is associated with baryte,

brochantite Brochantite is a sulfate mineral, one of a number of cupric sulfates. Its chemical formula is Cu4SO4(OH)6. Formed in arid climates or in rapidly oxidizing copper sulfide deposits, it was named by Armand Lévy for his fellow Frenchman, geologist ...

chalcocite Chalcocite (), copper(I) sulfide (Cu2S), is an important copper ore mineral. It is opaque and dark gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohs scale. It is a sulfide with a monoclinic crystal system. ...

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mo ...

chrysocolla Chrysocolla ( ) is a hydrated copper phyllosilicate mineral and mineraloid with formula (x<1) or . The structure of the mineral has been questioned, as a 2006 spectrographic study suggest material identified as ...

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...

, hematite, lindgrenite, molybdenite, powellite and

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

References

{{reflist Molybdenum minerals Orthorhombic minerals Copper minerals