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56 STRUCTURE. * umereni decrees surlacos are either flat, or uneven in • The flat surfaces are referred tn ft.;*, i,„„ 1 c i uneven .ones to fracture. cleavage, and the Other faces parallel to the flit ,, generally be discovered by splitting or I f • f 8 CX ?° S lna . y the mineral in the dea ™S *»« k1,£“ »^tS?„7, be dev ' f 1 T‘ 1 b? * a ™«""»» f separated at their surfaces h T* n ^ C1 7 atals > w hich are division or cleavage between a i W i. uc admit of no farther of planes which mav he r, 7 U ° i SUr . es > the other consisting from each other and anmn tT fl “‘definitely small distances mineral itself The first f fl , ( 0 " S to tbe structure of the union, and the second cleavage pll™ ^ ^ termei f ace « °J r dy; but tlm ^leavage^l geilendl - y n found in one direction : j• _ t.M'VflffC Tnttlies umifillv n/’/mi* m ... only; but the cleavaue oh, gener - y found in one direction directions, and freonfntl <,neS u , 8 T occur 111 two or more solid; and if the mor n ‘ US f° pr ° duCe a ^talliuc planes will generadv be n n T 1“ re S ular ?^ 8taIs > the cleavage the specimen hS- P JJ^ lel t0 80me of their {tu ' cs - When steel anvil, and be snht VI g °’ » I™ 7 be rest ? d 0,1 a small ’" hen less ’ a pair of . " 1 1 a small chisel and a light hammer; used; and ^ ™Y bc cleavage planes inT<Lu knde , 1 ? a . v , 1 ? e , sufficient to detect tho be firmly held betwo fi C ? 8 !! ’ ' vlllck > t° r this purpose, must CleavL* nh • 6 lorefin « er and thumb, the mineral under “""V 11 ^etennming the crystalline form of frequently be known • "tvT 10n ’.,; aud 7 w hich its species may exact angular measure u ° ff e,le rally afford moro thaU Can be ohtamcd from the faces of d unio n 0f n P ^ rOXC ; ne named sahlito affords an’instance of Planes in three direcfiT “w Mam P l08 , of ck ‘ ava K« cleavage the separaS of tho "f S nd - r th ° bcad of lime, and other minerals f ' a 8 of mica » su] l>hate of minerals of similar structure. structure. separate part^™mino«!i t0 ex P r08S tke nianner in which tho it can be ascertained bv mo?)™ a ^ r( '? a ted together, as far as The varieties of struct^ 1'“ d,8ru I ,tion of tbc n,a88 - Crystalline, wliero fV>n i i planes referred to in the nt ?•" 8Urfacos present tho cleavage Laminar, where P ? 8 . BeoUon - indefinitely thin plates in onlv r ° f Ra8 - V 8C P arat ion into J putes in only one direction, as in mica.