Flint Pebbles-Silica Pebbles

why flint pebbles is the most imported/used by main indian ceramic manufacturers in morbi ((hindi: मोरबी))? ·         our flint pebbles widely used as grinding media and filling material to grind the clumpy raw materials to the fine powder in ball mill. ·         compared to synthetic grinding media, flint pebbles has favorable ratio of price to performance. ·         have exceptional purity and better characteristic compared to french ones. ·         have less abrasion degrees, and is superior to crush characteristics