CALDERITE. 



Comp. CaC=carbonic acid 44, and lime 

 56 = 100 ; often with some carbonate of 

 magnesia or iron. 



BB infusible ; alone on charcoal it shines 

 with intense brightness when all the car- 

 bonic acid is expelled, and becomes con- 

 verted into pure lime or quicklime. With 

 fluxes behaves like Ai-agonite. Some varie- 

 ties, as that accompanying Garnet in Werme- 

 land, Laumonite in Brittany, shine with a 

 yellow phosphorescent light when laid on a 

 hot coal, or struck in the dark. 



Effervesces violently with acids. 



The purest form of Calcite is Iceland Spar, 

 which in common with other transparent 

 varieties is doubly refractive in a high de- 

 gree. The different species will be describ- 

 ed under their proper names. 



Localities. This mineral is so universally 

 distributed, that it is only possible to give 

 a list of its most remarkable localities. Six- 

 sided prisms of great beauty have been found 

 at Andreasberg in the Harz. In England 

 fine specimens are chiefly found in Cornwall, 

 Devonshire and Derbyshire; in Wales, in 

 Flintshire; in Scotland, at Strontian, Ar- 

 gyleshire ; and in Ireland, at Kingston Cave, 

 near Cahir, co. Clare. In Cornwall low 

 hexagonal prisms and tabular forms pre- 

 vail, like Jigs. 74 and 76. Fig. 82, repre- 

 sents the crystals from the Breakwater quar- 

 ries at Plymouth. This ^g. and figs. 79, 

 80, and 83, are the forms most common in 

 Derbyshire, and at Alston Moor; fig. 79, 

 being that called by the Derbyshire miner 

 "Dog's-tooth Spar." In the neighbour- 

 hood of Alston, and at Garrigill in Cum- 

 berland, the crystals have commonly a 

 hexagonal character, as represented in figs. 

 71, 73, 74, 77, 78, and 81. Fig. 77 repre- 

 sents a form met with at Dufton and Pat- 

 terdale in Westmoreland. 



Name. From the Latin calx, lime. 



Brit. Mus., Cases 42 to 47. 



M. P. G. Principal Floor, Wall-cases 27, 

 28, and 80 : Horse-shoe Case, Nos. 367 to 

 391. 



Calderite. a massive variety of Gar- 

 net from Nepal, 



Caledonite, Beudant, Greg §• Lettsom. 



CALOMEL. 



61 



Fig. 84. 



A 



Fig. 85. 



mountain-green if the crystals are delicate. 

 Lustre resinous. Translucent. Streak green- 

 ish-white. Rather brittle. Fracture uneven. 

 H. 2-5 to 3. S.G. 6-4. 



Comp. Cupreous sulphato-carbonate of 



Lead, or 6 Pb S + 4 PbC + 3 CuC. 

 Analysis by Brooke : 



Sulphate of lead . . . 55-8 

 Carbonate of lead . . . 32-8 

 Carbonate of copper . . 1]'4 



100-0 



BB on charcoal, easily reduced. 



Partially soluble, with slight efferves- 

 cence, in nitric acid. 



Localities. Found in flattish crystals 

 accompanied by other ores of lead, at Lead- 

 hills in Lanarkshire, and with Cerussite 

 and Leadhillite at Roughten Gill in Cum- 

 berland : also said to occur at Tanne in the 

 Harz, and at Mine la Motte in Missouri. 

 The crystals are generallv very minute, and 

 appear sometimes in small bunches radiating 

 from their common point of attachment to 

 the matrix. 



Brit Mus., Case 55. 



Callais. See Turqitois. 



Callaite, Allan, Fischer, Phillips, Nicol. 

 See TuRQUois. 



Callimus, J. Woodivard. The name 

 given to the stony matter contained in the 

 cavities of iEtites, when it is loose and 

 moveable. 



Calomel, Beudant. Pyramidal. Some- 

 times occurs crj'stallized in distinct quad- 

 rangular prisms terminated b^ pyramids : 

 also in tubercular crusts; sometimes fibrous, 

 rarely compact. Colour greyish -white 

 grey, yellowish, greenish-grey, brown : oc- 

 casionally translucent, with an adaman- 

 tine lustre. Sectile. Fracture conchoidal. 

 H. 1 to 2. S.G. 6-48 



Rhombic. Primary form a right rhombic 

 prism. Colour bfuish-green, inclining to 



Comp. Hg2 CI = chlorine 15-1, mercury 

 84-9 = 100. 



BB on charcoal, it is entirely volatilized if 

 pure. 



Localities. Large and well-defined crys- 

 tals of this rare mineral are found at Mos- 

 chellandsberg in Deux Ponts (Bavaria), 

 coating the cavities of a ferruginous gangue, 

 and associated with Cinnabar; it is also 

 met with at the quicksilver mines of Idria 



