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Very low concentrations of the heaviest lanthanides in monazite justified the term "rare" earth for these elements, with prices to match. Thorium content of monazite is variable and sometimes can be up to 20–30%. Monazite from certain carbonatites or from Bolivian tin ore veins is essentially thorium-free. However, commercial monazite sands ...
Poikiloderma vasculare atrophicans, or PVA, indicates that extra or altered skin pigmentation ("poikiloderma") [10] is occurring, associated with heightened visibity of capillaries ("vasculare", referring to telangiectasia) under the skin, related to thinning and wasting away ("atrophicans") of the skin and its tissue. Telangiectasia is an ...
Defatting is the chemical dissolving of dermal lipids, from the skin, on contact with defatting agents. This can result in water loss from the affected area and cause the whitening and drying of the skin which may result in cracking, secondary infection and chemical irritant contact dermatitis. [1]
Livedo reticularis is a common skin finding consisting of a mottled reticulated vascular pattern that appears as a lace-like purplish discoloration of the skin. [1] The discoloration is caused by reduction in blood flow through the arterioles that supply the cutaneous capillaries, resulting in deoxygenated blood showing as blue discoloration ().
It is the cerium-dominant analogue of monazite-(La), monazite-(Nd), and monazite-(Sm). It is also the phosphorus analogue of gasparite-(Ce). [ 3 ] The group contains simple rare earth phosphate minerals with the general formula of AXO 4 , where A = Ce, La, Nd, or Sm (or, rarely, Bi), and X = P or, rarely, As.
There is little difference in the three in terms of physical properties and most bastnäsite is bastnäsite-(Ce). Cerium in most natural bastnäsites usually dominates the others. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium, an important industrial metal. Crystal structure of bastnäsite-(Ce).
Fissure is a lesion in the skin that is usually narrow but deep. [29] [33] Induration is dermal thickening causing the cutaneous surface to feel thicker and firmer. [29] Atrophy refers to a loss of skin, and can be epidermal, dermal, or subcutaneous. [30] With epidermal atrophy, the skin appears thin, translucent, and wrinkled. [29]
Monazite-(Sm) is an exceedingly rare representative of the monazite group, with samarium being the dominant rare earth element in its structure. It is the samarium analogue of monazite-(Ce), monazite-(La), and monazite-(Nd). It is only the second known mineral with samarium being the mineral-forming element, after florencite-(Sm). [3]