How is Silestone made?

Silestone is a brand of a Spanish Group called Cosentino. The Silestone brand has somehow been associated to the product, and what some call Silestone is in fact an engineered stone. The technology is Italian, from Breton, they have currently about 12 production lines, and have lines specialized per colour. One of the main problems with these plants are the possible contamination that may occur when changing from a dark colour to a light colour, although cleaning is a normal task it's almost impossible to get it 100% clean.
The mixture uses polyester resin, in different proportions it can vary from 7% to 10% (or even more). What establishes the quantity of resin? ... one variable is the grain size of the filler, the bigger the less resin is necessary for a good mix. Besides, resin, they'll use all types of material ... but mainly quartz. Some companies also use silica sand, the advantages are pricing, but it's not as good as quartz. Other components normally used, crushed glass, colouring pigments, other special stones or minerals to give special effects and chemicals to control the cure and the bonding.
The secret of the business is how do they do it, as the technology is wide spread, and basically every Breton plant has more or less the same technical capacity ... now not everyone has a whiter white ...