Hardwicke's science-gossip : an illustrated medium of interchange and gossip for students and lovers of nature . be principally orthoclase, but albite L 2 220 HARDWICKES SCIENCE-GOSSIP. is also a very general constituent of these granites, as isalso microcline. There are both white and blackmicas the former being described as margarodite, bythe Rev. Dr. Haughton, who, judging from the meanderived from several analyses, believes that theamount of water of crystallization present differen-tiates it from the variety known as muscovite. Theisolated masses before referred to, give good illustra-tio
Hardwicke's science-gossip : an illustrated medium of interchange and gossip for students and lovers of nature . be principally orthoclase, but albite L 2 220 HARDWICKES SCIENCE-GOSSIP. is also a very general constituent of these granites, as isalso microcline. There are both white and blackmicas the former being described as margarodite, bythe Rev. Dr. Haughton, who, judging from the meanderived from several analyses, believes that theamount of water of crystallization present differen-tiates it from the variety known as muscovite. Theisolated masses before referred to, give good illustra-tions of the hexagonal or lozenge-shaped plates, andmay be studied with interest, as the form in whichmica usually appears in granite does not afford theinformation to a beginner. A peculiarity in thefelspathic and eurite portions of this granite, consistsin there being a number of crystals of a reddish-yellowcolour scattered through the mass. These are veryminute, none of them exceeding the size of a smallpins head, but they are translucent, with a highvitreous lustre. Closer inspection reveals certain ^7—^. Fig. 126.
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