Product classification and quality grading
By dividing our blocks into different classes depending on appearance and colour variation, we make it easier for you to assess their quality without having to see it in reality. We generally supply three types of block: block stone, ton stone and rock stone. These are then classified into several different categories. Some quarries have specific classifications, which can be found under ‘Extra definitions of block classes’.
A block stone is hewn into a rectangular block, with dimensions suitable for making countertops, monuments and similar products. Each block is assessed individually and classified according to a scale based on aspects such as colour, structure, crystalline deposits and cracks. All our blocks are sold by volume (cubic metres).
A ton stone is an unhewn block with no major colour variations and with cracks in the direction of sawing only. They are not dressed by us, as this would give them dimensions unsuitable for making slabs for countertops, memorials and so on. For a block to be classed as ton stone, it must still be possible to extract one or more headstone components and/or countertops, or some other construction product. Each ton stone is assessed individually and classified according to a scale based on aspects such as colour, structure, crystalline deposits and cracks. All our ton stones are sold by weight (tonnes).
A rock stone is an undressed block that may contain colour variations and cracks. It can almost only be used for cutting into paving stones and kerbstones, and for making vases and other decorative objects. Rock stone is classified based on how much of the material can be extracted as paving stones. All our rock stones are sold by weight (tonnes).
Extra definitions of block classes
Apart from the general classification of block and ton stone, there are further definitions specific to particular block classes, depending on the type of stone. For instance there may be large grains, specific colour variations or colour marks present which mean the block cannot be used for memorials or only in exterior construction.