Bush Hammer
The needle tip is a device that is hammered and hammered to the surface of the stones, 
which is called stone hammer or needle bosom. The use of the Hammer bush stone on openings for the
purpose of friction and preventing frustration.

What is a limestone used for?
Limestone, quicklime and slaked lime are all used to neutralise excess acidity - which may be caused by acid rain -
 in lakes and in soils. Limestone is used as a building material, and to purify iron in blast furnaces. It's also used 
in the manufacture of glass, and of cement (one of the components of concrete).

What are the different types of limestone?

Limestone. Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral,
 forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms 
ofcalcium carbonate (CaCO3). About 10% of sedimentary rocks are limestones.