Bulletin . rally free from any detrimentalimpurities, except black tourmaline and biotite, and these are rarelyassociated in the same dike. Garnets are present in a few of thesedikes, but rarely in sufficient quantity to seriously injure the occurs in most of these dikes, and, as a rule, is confined tolimited zones, which permits of its easy removal in mining, or is suffi-ciently coarsely crystalline to permit of its elimination by cobbing. The feldspar of these deposits is a pale buff to pale cream micro-cline. The associate quartz is chiefly of the smoky variety, beingalmos
Bulletin . rally free from any detrimentalimpurities, except black tourmaline and biotite, and these are rarelyassociated in the same dike. Garnets are present in a few of thesedikes, but rarely in sufficient quantity to seriously injure the occurs in most of these dikes, and, as a rule, is confined tolimited zones, which permits of its easy removal in mining, or is suffi-ciently coarsely crystalline to permit of its elimination by cobbing. The feldspar of these deposits is a pale buff to pale cream micro-cline. The associate quartz is chiefly of the smoky variety, beingalmost black in some deposits near Mount Rubellite, in the easternpart of this district. Massive sugar-quartz occurs in many of thesedikes, and in the neighborhood of Paris is a fine grade of rose quartz. The irregular lenses of feldspathic rock which are distributedthrough this district can hardly be said to constitute a source offeldspar supply because the feldspar is so hopelessly mixed with other BULLETIN 92. A. WEATHERED PEGMATITE DIKE AT EAST ORLAND,
Size: 1906px × 1311px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
