MONAZITE
MONAZITE Monazite – (Ce,La,Th,Sm)PO4 – is a common phosphate. It was an important ore of Th, La and Ce, before the world market for Rare Earth Elements was dominated by the Mongolian occurrences exploited by China. It still remains as REE ore, but on a very small scale. “Monazite” nowadays no longer designates a mineral […]
MERCURY
MERCURY Native mercury – Hg – is a rare native element that has a number of industrial uses, both historical and current. Native mercury, being a liquid at room temperature, does not meet the criteria required to be a mineral, constituting a mineraloid. For historical reasons, however, it is listed as a mineral species. At […]
MAGNETITE
MAGNETITE Magnetite – Fe3O4 – is a very common oxide, occurring in many types of rocks. It has enormous importance as ore of Fe, V and Ti, among others. It participates in the composition of many other types of ores. Magnetite is the most magnetic mineral known and may contain Ti, Mn, Mg, Zn, Ni, […]
MILLERITE
MILLERITE Millerite – NiS – is a very rare sulfide that integrates Ni-Co-Ag ores. It has a very typical habit, almost always forming radial aggregates of acicular crystals, elongated parallel to (0001). Due to its resemblance to pyrite, the mineral has been nicknamed “hair pyrite”. Isolated crystals can be helicoidal or form rings. When massive, […]
MALACHITE
MALACHITE Malachite – Cu3(CO)2(OH)2 – is a fairly common carbonate, by far the most abundant alteration product of primary Cu minerals such as chalcocite and chalcopyrite. Malachite has been an important copper ore since prehistoric times and usually occurs in subordinate amounts in copper ores. It was used as a pigment and is a decorative […]
MUSCOVITE
MUSCOVITE Muscovite – KAl3Si3O10(OH)2 – is a very common phyllosilicate of the Mica Group that occurs in many types of magmatic, metamorphic and sedimentary rocks. Like other micas, it has a number of important industrial uses. As muscovite also forms in pegmatites, the crystals can be enormous: the record is a crystal measuring 4.5 […]
MICROCLINE
MICROCLINE Microcline – KAlSi3O8 – is a very common tectosilicate, an important rock-forming mineral of granitoid rocks. It is an important industrial mineral for the manufacture of porcelain, also ceramics and glass. Microcline almost always is twinned according to various laws, which greatly simplifies its recognition under the microscope. More common are the polysynthetic twins […]
MINIUM
MINIUM Minium – Pb3O4 – is a very rare oxide, a secondary mineral of lead. It participates in the secondary mineral assembly of polymetallic ores, but is never the main ore mineral. Macroscopically, it can be confused with litharge (tetragonal PbO, also very red) and with powdery cinnabar (HgS). As it contains lead, it is […]