HAMILTON ON THE GEOLOGY OF TUSCANY. 293 



agent in the formation of the ore. The amount raised in the year 

 ending September, 1843, was 1,894,765 Tuscan pounds. 



In the vicinity of the j unction of the serpentine and gabbro, a 

 rather remarkable substance is occasionally found, called Losima. 

 It is generally of a bright red colour, extremely shining and bril- 

 liant, soft and soapy to the touch, and apparently argillaceous. 

 It is perhaps the result of friction. In carrying a gallery to the 

 N.E., for the purpose of communicating with a new shaft, the 

 miners have traversed another mass of serpentine ; but very slight 

 indications of ore have as yet been perceived in it. The strike of 

 these masses of serpentine, or dykes as they may perhaps be called, 

 is from N. W. to S. E., which coincides with the direction of ano- 

 ther serpentine dyke which I traced some way over the hills to 

 the S.W. of La Cava. It may be observed, too, that their direc- 

 tion is parallel to that of the principal mountain chain in this 

 part of Italy. 



Veins of steatite (or soap-stone, Pagoda stone, pietra di sarto, 

 as it is here called), which sometimes assumes a very asbestos form, 

 occur frequently in the serpentine ; and this is a considerable 

 object of export commerce. One of the localities where this 

 steatite is found, is remarkable from the occurrence of numerous 

 veins or layers of carbonate of lime, perhaps deposited by cal- 

 careous springs rising up through the serpentine, or it may be 

 the result of chemical segregation, by which the steatitic particles 

 were separated from the lime, and formed into distinct nodules. 

 Perhaps the different appearances would justify both suppositions. 

 At Monte Rufoli, the serpentine extends over a considerable 

 tract of country, covered with magnificent forests of ilex, which 

 render its examination almost impossible. Here, however, the 

 rock is remarkable for being the seat of the quarries of chalcedony, 

 which supply the beautiful agates used in the Royal and other 

 manufactures of pietra dura at Florence. 



About two miles east of Monte Rufoli, and on the slope of the 

 hills facing the valley of the Sterza, are the chalcedony quarries. 

 At first their appearance resembles that of quartz dykes, rising 

 up through the serpentine, and forming a low wall, a few feet 

 above the ground. Wherever they have been worked, however, 

 they appear to cease about eight or ten feet below the surface, thus 

 leaving a kind of ditch on the hill side, about three or four feet 

 wide, and varying in depth from eight to ten feet. Besides tlfese 

 principal dykes or masses, of which there are said to be several, 

 although I only saw two, the serpentine is traversed in various 

 directions by small, irregular veins of chalcedony, generally of a 

 reddish colour : other similar masses of siliceous substances overlie 

 the serpentine, as if spread over the surface from the larger 

 dykes, differing both in character and appearance, and representing 

 every possible variety of chalcedonic and agate bodies. They 

 contain numerous cavities, the inner coats of which are covered with 

 botryoidal and mammillary chalcedony ; also masses of concretion- 

 ary, whitish -grey, earthy chalcedony, with a gradual shading from 



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