Stone Defects Description
Common defects on stone material include cracks (or fractures), patches (or blotches), bands, lines, color variations and pattern variations. The existence or size of these defects is the gauge to classify the quality grade of the stone products.
Also known as fracture. It is a separation of an object / material into 2 or more pieces under the force of stress. Cracks are mainly caused in two ways: (1) natural cracks/fractures caused by mother nature in the raw material itself at the quarry level (2) Man-made causes, this is primarily an isse during the production and handling processes.
Patches are also referred to as blotches. It may or may not be same color as the stone, due to inherent properties present in the mineral deposits. It occurs only due to natural causes & is uniquely characteristic in that particular Block.
It is a continuous patch, which runs along the surface of the slab. If the size of a patch exceeds 30cm length and 2cm width it is considered a band. The appearance of a band is like a thick line running across the surface of the slabs.
A line occurs due to inherent mineral properties in a slab. The size of a line can be 1-10mm in thickness and 1 foot to 10 feet in length.
Defined as non-uniformity of the color in a particular slab. It disturbs the pattern balance of the slabs. In certain cases slabs appear two-toned.
If the grain structure/pattern occurs in a way that appears contradictory to the acceptable norms, it is termed as pattern variation.