*Would take the disclaimer with a LARGE serve of salt ;)!! ..however,beautiful Unique pigments..just use the ASTM to guide you*"BLOCKX:Rare, tough pigments are thoroughly crushed, then coated in gum arabic and honey. They come to you, today, in 72 brilliant shades. We do not and never have prepared transient or unstable shades. A classification by degree of stability would, therefore be out of place..."