THE MARBLES OF ITALY. 151 



Variegated Marbles. — The most beautiful among the breccias 

 known to us in Italy are those of Terra di Lavoro, but they are not 

 quarried for sale ; some of the alpine varieties are extremely valuable ; 

 that of Coregna, near La Spezia, is very beautiful, but its excessive hard- 

 ness necessarily prevents it from being very largely used. The mountains 

 extending from Carrara to Seravezza are also remarkable for the ex- 

 excellence of their produce in this particular class, as will be seen by 

 an examination of the breccias and mischi of Seravezza, Massa, and 

 Carrara. The light and dark coloured mixed marbles (mischi), the 

 breccias known as affricano, the breccias of Eondone, and other 

 localities, the persichino of Corchia, and Vallata di Renaia, and the 

 paonazzi of Laghetto, Finocchioso, Cava di Sponda, Boccanaglia, &c, 

 are all very brilliant and costly marbles, 



Breccias. — The breccias of the metalliferous chain are formed of 

 fragments of highly crystalline limestone, united together by a siliceo- 

 calcareous cement, containing an admixture of a hornblendic substance, 

 which is eminently hard and resistant to the action of the atmosphere. 

 The cement is due to a particular action of the adjacent masses or veins 

 of iron ore, which are found in contact with the rocks in question. The 

 hornblendic cement, with its iron or manganese base, produces the 

 variegated appearance resembling the peacock's tail, and rose colour, 

 peach blossom, and other delicate tints, which may be seen in the 

 specimens from the different localities. 



As may be imagined from their composition, these rocks are, as 

 a rule, very impervious to ordinary atmospheric agencies. Examples 

 of this fact are furnished by the mischi and affricano of Seravezza, 

 employed in some of the principal monuments of Florence. 



The great column which formerly stood in the square of San Felice, 

 but which has been lying on the ground for many years, exposed to the 

 action of atmospheric water, has in nowise been injured by such un- 

 favourable treatment. The tenacity with which the Porto Santo, the 

 Affricano, the Brillante, the Paonazzo, and other varieties retain their 

 polish is another valuable quality which renders them eminently 

 adapted for the more costly class of decorative works. 



The whole of the Italian calcareous formations, of all ages, furnish 

 a supply of excellent marbles from the miocene lumachella, down to 

 the upper triassic and muschelkalk limestones, and perhaps those of 

 an older period. 



The best known and most esteemed marbles are, as has already been 

 seen, principally obtained from Tuscany. 



The white marbles of saccharoidal structure are those which are now 

 principally preferred by sculptors. The most perfect blocks that could 

 possibly be obtained are those of lamellar structure, derived from the 

 quarries of Campigliese and the island of Elba. As regards saccharoid 

 marbles, they are exclusively obtained from the Apuan Alps, and more 



