thomsonite (th ast)

[After R. D. Thom son; suff. -ite ( Min.).] Min.: A member of the group of Zeolites. Crys tall i zati on, orthorhombic, occurring as individual crystals but more often in radiated groups, also compact. Hardne , 5-5.5; specific gravity, 2-324; luster, vitreous to pearly; color when pure, snow-white; brittle; pyroelectric. Composition: Silica, 38-9; alumina, 31'6; lime, 12-9; soda, 4.8; water, 138=100. Formula 2SiO2Al2O3(2CaO+1NaO)2 HO. Prof. James D. Dana divides as follows: 1. Ordinary: (1) in regular crystals; (2) in slender prisms, sometimes radiated; (3) radiated fibrous; (4) spherical aggregations of radiated fibers or crystals; (5) ma ive: 2. Mesole: including scoulerite: 3. Chalilite. Occurs in cavities in old amygdaloidal lavas, and sometimes in so-called metamorphic rocks. thong, *thwang, *thwangue, *thwong, subst . [A.S. thwang ; cogn. with Icel. thvengr =a thong, a shoe-latchet. From the same root as TWINGE(q.v.).] TWINGE(q.v.).] A leather strip or lash; a strap of leather used for fastening anything. "At the seams, where the different skins are sewed together, they are commonly ornamented with ta els or fringes of narrow thongs , cut out of the same skins."Cook: Third Voyage , bk. iv. ch. v.