MURIATE OF LEAD. 

 MuRiATE OF Lead, Phillips. See Men- 



DIPITE. 



Muriate of Mercury, Phillips. See 

 Calomel. 



Muriate of Potash. See Sylvine. 



Muriate of Silver, Phillips. See 

 Kerargyrite. 



Muriate of Soda, Phillips. See Com- 

 mon Salt, 



MuRTATED Antimoky, Kirwan. See 

 Valentinite. 



Muriatic Acid. Is emitted in a gaseous 

 form from the craters of active volcanoes, 

 and is sometimes found in solution in cre- 

 vices about their slopes. 



Murio-carbonate of Lead, Phillips- 

 See Cromfordite, 



Muromontite, Kerndt. Probably a 

 variety of AUanite, found in grains rarely 

 exceeding half a pea in size. Colour black ; 

 slightly greenish by reflected light. Colour 

 of powder greyish-white, with a tinge of 

 grev. Lustre vitreous. H. nearly 9. S.G. 

 4-26. 



Comp. 3K Si + ( Al Be) Si. 





Analysis, by Kerndt : 





Silica .... 



. 31-09 



Alumina 



. 2 24 



Glucina 



. 5-52 



Yttria .... 



. 37-14 



Protoxide of cerium 



. 5-54 



Protoxide of lanthanum 



. 3-54 



Protoxide of iron . 



. 11-23 



Magnesia 



. 0-42 



Protoxide of manganese 



. 0-91 



Lime .... 



. 0-71 



Soda . ^. . . 



. 0-65 



Potash. 



. 0-17 



Water and loss . 



. 0-85 



100-00 



BB glows like Gadolinite: fusible only 

 at the edges after long heating. 



Locality. Mauersberg and Boden, near 

 Marienberg, in the Saxon Erzgebirge. 



MuRRHiNA of the ancients, was probably 

 a kind of Agate. 



Muscovite, Dana. Muscovy Glass, 

 Woodward. Rhombic. Chiefly occurs in 

 rhombic or hexagonal tables, with a perfect 

 basal cleavage; also in scales and scaly- 

 massive. Colourless, or grey, pale gree'n, 

 and olive-green, red, brown, black and yel- 

 low. Lustre pearly. Transparent to trans- 

 lucent. Sectile ; flexible and elastic in 

 thin laminai. Streak white to grey. Biaxial. 

 Colours in direction of the axis and dia- 



MUSCOVITE. 247 



meter frequently different. Very tough. 

 H. 2 to 2-5. S.G. 2-75 to 3-1. 



Fig. 296. 



Fig. 297. 



^kf^ 



Fig. 29S. 



Comp. (R2 «5) yi or 3AI fei + K Si. 



Analysis, from Uto, bv H. Rose : 

 Silica . . . " . . 47-50 

 Alumina .... 37-30 

 Peroxide of iron . . . 3-20 

 Peroxide of manganese . 0-90 



Potash 9-60 



Hydrofluoric acid . . 0-56 

 Water 2-63 



101-59 



BB fuses with difiiculty to a greyish- 

 yellow blebby glass. 



Kot decomposed by muriatic or sulphuric 

 acid. 



Localities. — English. Cornwall, St. Den- 

 nis. Saddleback and Brandygill, Cumber- 

 land. — Scotch. Rubislaw and Auchindoir, 

 Aberdeenshire ; of a pinkish-brown colour, 

 in granite. Portsoy, Banffshire, plumose. 

 In dark-brown hexagonal plates at Coire 

 Bhradau, Buteshire. — Irish. Killiney, 

 Dublin, in fine plates in granite. Plumose 

 at Three Rock Mountain. In perfect crystals 

 in the granite of the Mourne Mountains, 

 CO. Down, figs. 296 — 298. — Foreign. Finbo, 

 Sweden. Skutterud in Norway. Siberia. 

 New Hampshire, U.S., in transparent plates. 

 Crystallized at Vesuvius, St. Gotthard, Par- 

 gas, Arendal, Uto, Fahlun, &c. Schwartzen- 

 stein in the Tvrol. (See Fuchsite.) 



Brit. Mus., Case 32. 



Muscovite is abundant in granite, of which 

 it forms one of the constituents ; also, in 

 gneiss, syenite, mica-slate, and other rocks. 

 In Siberia, and at Ackworth, Grafton, and 

 Alstead in New Hampshire, U.S., it is met 

 with in perfectly transparent plates, some- 

 times more than a yard across. The name 

 Muscovy glass originated in the use of these 

 plates in Russia for lanthorns and windows 

 instead of glass. It has also been adopted 

 in the Russian navy as a substitute for 

 window-glass, in consequence of its not be- 

 ing liable to be broken by the concussion 

 caused by the firing of heavy guns. It is 

 likewise used as a substitute for Avindow- 

 glass in Siberia, Peru, Pennsylvania, &c. 

 Advantage has been taken of its transpar- 

 R 4 



