Quarrying And Dressing

Granite is quarried either by wedging or by blasting. The former process is generally reserved for large blocks, and the latter for smaller pieces and road-metal.

It is better to have the blocks cut to the desired forms in the quarries; first because it is easier to square and dress the stone while it contains the moisture of the ground or " quarry-sap;" also because the local men, being accustomed to the stone, are able to dress it better and more economically, and part of the work can be done by machinery, generally to be found at the principal quarries. Moreover, the bulk of the stones being reduced by dressing, the cost of carriage is saved, without much danger of injuring the arrises in transit, as the stone is very hard.

1 Page's Practical Geology.

2 Wray On Stone.

Uses To Which Granite Is Applied

Granite is used chiefly for heavy engineering works, such as bridges, piers, docks, lighthouses, and breakwaters, where weight and durability are required. It is also used especially for parts of structures exposed to blows or continued wear, such as copings of docks, paving, etc. The harder varieties make capital road metal.

In a granite neighbourhood the stone is used for ordinary buildings; but it is generally too expensive in first cost, transport, and working, and is therefore reserved for ornamental features, such as polished columns, pilasters, heavy plinths, etc.

The granular structure and extreme hardness of granite render it ill adapted for fine carving, and its surface is entirely destroyed by the effects of fire.