PUMICE. AZURE STONE. 67 
part of a stream that had flowed from a volcano. It is 
also found in Sicily, and several other islands of the 
Mediterranean ; and in nearly all parts of the world 
where there are volcanoes. 
108. PUMICE is an extremely light and porous mineral, 
of somewhat fibrous texture, and of white, grey, reddish, 
brown, or black colour. 
From the texture of this mineral, which is chiefly 
brought from the neighbourhood of volcanoes, some 
persons have imagined it to be asbestos decomposed by 
the action of fire. Its lightness is such that, placed in 
water, it will float. 
To mechanics and other artists purnice stone is a 
very useful mineral. It is employed for cleansing and 
smoothing the surface of wood, leather, metal, stones, 
glass, and other substances ; and it is used by parch- 
ment-makers, curriers, and hat-makers. Hence it forms 
a considerable article of trade : and is exported from 
the Lipari Islands, in great quantities, to the different 
countries of Europe. Sailors in the Mediterranean 
rub their beards off with pumice, instead of shaving. 
On account of its porosity, it is used in Teneriffe as a 
filtering stone. It forms a pernicious ingredient in 
some kinds of tooth powder ; and in Italy is ground 
and used instead of sand, in the making of mortar. 
Pumice occurs in Ireland, along with obsidian (107) ; 
and it abunds in several islands of the Grecian 
Archipelago. 
AZURE STONE FAMILY. 
109. LAPIS LAZULI, AZURE STONE, or LAZU- 
LITE, is a mineral of azure-blue colour in Tarious shades, 
and generally accompanied with white or clouded spots, and 
also with pyrites (236) , which have the appearance of golden 
veins or spots. Its texture is earthy, and fracture uneven. It 
is opaque, or nearly .so, and, in some parts, is sufficiently hard 
to strike fire zcith steel. We are not informed that lapis la- 
zuli is otherwise found than in shapeless masses or lumps. 
