SCANDIUM 



569 



might speculate further that the pegmatite is actu- 

 ally unusual. If it is unusual, the massive quartz 

 body mentioned by Geach (1963) would be an asym- 

 metric core, the fluorite bodies an intermediate zone, 

 and the radioactive layers the wall zone. 



The Crystal Mountain deposit has been actively 

 mined for fluorspar since 1952, but there is no indi- 

 cation that thortveitite or other minerals have been 

 recovered. 



The influence of host rock on the scandium con- 

 tent of pegmatites has been long considered and is 

 discussed by Neumann (1961) and Phan, Foissy, 

 Kerjean, Moatti, and Schieltz (1967). Amphibole- 

 bearing rocks seem definitely favorable for scandium 

 pegmatites, but an amphibolite host rock is no assur- 

 ance that a pegmatite will be enriched in scandium. 



GREISEN AND VEIN DEPOSITS 



Metasomatic deposits containing minerals of 

 tungsten, tin, or beryllium in association with 

 quartz, muscovite, topaz, or tourmaline are found in 

 or near granitic bodies from which they, and re- 

 lated high-temperature veins, presumably were de- 

 rived. These deposits, called greisens, are apt to 

 contain minerals with anomalously high scandium 

 content. According to Borisenko (1963), the main 

 scandium carriers in greisens are wolframite, cas- 

 siterite, beryl, and micas. 



Wolframite is commonly the richest in scandium 

 of the greisen minerals and may contain up to 0.4 

 percent SC2O3, although the average content is con- 

 siderably lower. Where wolframite occurs in both 

 greisen and associated high-temperature veins, the 

 scandium content of the wolframite may differ. In 

 the Lake George area, Colorado (Hawley, 1969), 

 wolframite from greisen contained 0.3 percent scan- 

 dium as compared to 0.07 percent in wolframite 

 from a quartz vein in greisenized wallrock. 



Scandium enrichment is uncommon in deposits 

 that would be considered normal hydrothermal veins, 

 and even wolframite and cassiterite from these veins 

 generally do not contain more than 0.005 percent 

 SC2O3 (Vlasov, 1964). Ross and Rosenbaum (1962), 

 however, give an analysis of Colorado ferberite 

 (FeWOi) ore, presumably from the low-temperature 

 hydrothermal veins of Boulder County, that shows 

 a scandium content of 0.01 percent. 



VARISaTE DEPOSITS 



Sterrettite, one of the few minerals in which 

 scandium is a major component, occurs sparsely in 

 a highly brecciated zone in limestone at Fairfield, 

 Utah. It is associated with a large suite of phosphate 

 minerals of which variscite, A1(P04)2-2H20, and 



crandallite, CaAl(P04)2(OH)5H20, are the most 

 common. 



In addition to its occurrence in sterrettite, scan- 

 dium has been found in the associated phosphate 

 minerals, notably crandallite and variscite, which 

 contain from 0.01 to 0.8 weight percent SC2O3. A 

 small amount of scandium oxide was produced from 

 4,000 pounds of crude ore from the limestone de- 

 posit. The ore contained crandallite, variscite, chert, 

 and limonitic clay and averaged 0.10 percent SC2O3 

 (Frondel and others, 1968). 



The deposit at Fairfield is thought to have formed 

 under near-surface conditions by the precipitation 

 of phosphate dissolved by ground water from the 

 overlying Phosphoria Formation (Larsen, 1942). 

 The average scandium content of the Phosphoria is 

 0.001 percent (Gulbrandsen, 1966), but analyses of 

 phosphatic shale from the Fairfield area were found 

 by Ross and Rosenbaum (1962) to contain as much 

 as 0.05 percent scandium. 



Anomalous amounts of scandium have been found 

 in variscite deposits in the Western United States; 

 the origin of the deposits and their relationship to 

 the Phosphoria Formation seems to be quite similar 

 to the origin and relationship of the Fairfield de- 

 posit (Frondel and others, 1968), which is the 

 richest deposit found so far. 



ENRICHMENTS IN OTHER MATERIALS 



Scandium in concentrations greatly above crustal 

 abundance has been found in many geologic mate- 

 rials and mill products, including coals, titaniferous 

 magnetite ores, bauxites, nickeliferous laterites, and 

 some placer deposits (Ross and Rosenbaum, 1962; 

 Vlasov, 1964). None of these sources may be said 

 to constitute a scandium deposit, but some may be 

 considered potential sources of scandium as a by- 

 product of other commodities. 



RESOURCES 



If an important use developed for scandium that 

 would require tons rather than grams or kilograms 

 of the metal annually, what would be the most 

 logical source? Considering the amount of thortvei- 

 tite produced from pegmatites in Norway and Mada- 

 gascar, pegmatite sources would be inadequate. 

 Variscite deposits, such as at Fairfield, Utah, might 

 supply a few pounds, but soon they would be ex- 

 hausted. It is reasonable, therefore, to consider the 

 lower grade deposits from which scandium might 

 be produced as a byproduct. Tungsten ore concen- 

 trates, including concentrates of wolframite, hueb- 

 nerite, and ferberite, are one important possible 

 source. According to annual reports of the Climax 



