n6 Calcareous Genus. Violet marbles or limeftones vary much in den- lity; that of the violet marble of Valentia is 2,656, or 2,680; tbat of Maffia, near Lifbon, 2,723 5 t h at °* R°tne 2,755. The variegated marble of Florence ovves its deutritical hgures to mahganefe. 1 Chy. Ann. 1785, 57. The marble called Lumacbdli, found at Bley- berg in Carinthia, owes its fplendour to Ihells agglutinated by a grey or brown calcareous mat ter with argill and iron. Belides the charadfers ariling from texturc and colour, there are other dittinttions ariling from compofition, which are of confiderable import- ance for oeconomical phrpofes; for inftance, the diftinflion of fat and meagre limeftones, as the workmen call thcm. T he fat, or thoie which being converted into lime take up the greateft quantity of fand, are much eüeemed by mercenary architedts, as fand is the cheapeft ingredient. Meagre lime takes up lefs fand, yet forms a harder mortar even in water. Mr. Smcaton re- marked, that all ftones which afford a bufi-co- lourcd lime are of this fort. Eddyftone, § 171. Bo allo are thofe that afford a dark or blackifh lime, according to Mr. Bergman, who firft dif- covered that this property proceedcd from the manganefe contained in the lime, 2 Berg. 229. lt is'however faid, that a certain proportion of filex and iron pre-exifting in the ffone contributes not a little to this property, 2 Sauffi 115» *4°» and much I believe depends on the ftate in which the iron exifts in it, as fhall be fee« in treatlng of Pouzzolana. Of the ftones in which this property has bcen principally noticed, authors have