Hash index gauge misali grindability kwal samfurin yafi amfani da kayan aiki daidaitawa, dubawa da kuma sakamakon lissafi da sauransu a cikin grindability index gauge kwal. An auna misalin kwal ta Babban Cibiyar Nazarin Kimiyya ta Kwal ta Beijing ta amfani da Amurka ta shigo da Hasselometer, bayan sarrafa ƙididdigar bayanan gwaji, an ƙayyade daidaitaccen darajar, sakamakon daidai ne da abin dogaro. Kowane daidaitaccen samfurin ya ƙunshi samfuran kwal guda huɗu, daidaitaccen darajar su kamar haka: