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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 containing amethyst and citrine, from Bolivia.
Lanthanites are a group of isostructural rare earth element (REE) carbonate minerals. This group comprises the minerals lanthanite- (La), [ 3 ][ 4 ] lanthanite- (Ce), [ 5 ] and lanthanite- (Nd). [ 6 ] This mineral group has the general chemical formula of (REE) 2 (CO 3) 3 ·8 (H 2 O). Lanthanites include La, Ce, and Nd as major elements and ...
Crystal. Crystals of amethyst quartz. Microscopically, a single crystal has atoms in a near-perfect periodic arrangement; a polycrystal is composed of many microscopic crystals (called "crystallites" or "grains"); and an amorphous solid (such as glass) has no periodic arrangement even microscopically. A crystal or crystalline solid is a solid ...
Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. [3] The most common species of the group is monazite- (Ce), that is, the cerium-dominant member of the group. [4] It occurs usually in small isolated crystals.
The garnet group has a general formula of X 3 Y 2 (SiO 4) 3, where X is a large eight-fold coordinated cation, and Y is a smaller six-fold coordinated cation. There are six ideal endmembers of garnet, split into two group. The pyralspite garnets have Al 3+ in the Y position: pyrope (Mg 3 Al 2 (SiO 4) 3), almandine (Fe 3 Al 2 (SiO 4) 3), and ...
A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO 2+n] 2n−. Although depicted as such, the description of silicates as anions is a simplification. Balancing the charges of the silicate anions are metal cations, M x+. Typical cations are Mg 2+, Fe 2+, and Na +.
Belite is the mineral in Portland cement responsible for development of "late" strength. The other silicate, alite contributes "early" strength, due to its higher reactivity. Belite reacts with water (roughly) to form calcium silicate hydrates (C-S-H) and portlandite (Ca (OH) 2) according to the reaction: This rapid reaction is "chemically ...
References. [2][3][4] Orthoclase, or orthoclase feldspar (endmember formula K Al Si 3 O 8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture", because its two cleavage planes are at right angles to each other. It is a type of potassium feldspar, also known as K-feldspar.