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Tremolite is a member of the amphibole group of silicate minerals with composition Ca 2 (Mg 5.0-4.5 Fe 2+ 0.0-0.5)Si 8 O 22 (OH) 2. Tremolite forms by metamorphism of sediments rich in dolomite and quartz, and occurs in two distinct forms, crystals and fibers. Tremolite forms a series with actinolite and ferro-actinolite.
Actinolite is an intermediate member in a solid-solution series between magnesium-rich tremolite, Ca 2 (Mg 5.0-4.5 Fe 2+ 0.0-0.5)Si 8 O 22 (OH) 2, and iron-rich ferro-actinolite, ☐Ca 2 (Mg 2.5-0.0 Fe 2+ 2.5-5.0)Si 8 O 22 (OH) 2. Mg and Fe ions can be freely exchanged in the crystal structure. Like tremolite, asbestiform actinolite is ...
Anthophyllite is the product of metamorphism of magnesium-rich rocks, especially ultrabasic igneous rocks and impure dolomitic shales.It also forms as a retrograde product rimming relict orthopyroxenes and olivine, and as an accessory mineral in cordierite-bearing gneisses and schists.
Asbestos (/ æ s ˈ b ɛ s t ə s, æ z-,-t ɒ s / ass-BES-təs, az-, -toss) [1] is a group of naturally occurring, toxic, carcinogenic and fibrous silicate minerals.There are six types, all of which are composed of long and thin fibrous crystals, each fibre (particulate with length substantially greater than width) [2] being composed of many microscopic "fibrils" that can be released into ...
Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...
Other asbestiform minerals include riebeckite, an amphibole whose fibrous form is known as crocidolite or "blue asbestos", and brown asbestos, a cummingtonite-grunerite solid solution series. The United States Environmental Protection Agency explains that, "In general, exposure may occur only when the asbestos-containing material is disturbed ...
Tremolite was discovered in 1789. [2] Hexagonite, a varietal form of tremolite, has a Mohs hardness of 5.0-6.0. [3] Like tremolite, it is a calcium magnesium silicate hydroxide with the formula: Ca 2 Mg 5 (Si 8 O 22) 2. [3] The mineral was given the name, hexagonite, because its crystal structure was believed at one time to be hexagonal.
Ferro-actinolite is the ferrous iron-rich endmember of the actinolite-tremolite continuous solid solution series of the double chain calcareous amphibole group of inosilicate minerals. All the series members belong to the monoclinic crystal system.