The logs are cut into slices, then polished with infinite patience to obtain a flawless shine. These stone trees naturally have ever-changing bright colors and pockets of quartz, amethyst and other minerals. Their beauty only appears after polishing. The polished surface is so hard that it is absolutely invulnerable. Only diamonds can scratch it... Unlike marble, for instance, and just like glass, petrified wood is totally non-porous and thus stain-proof. The beauty of a petrified wood slab will always be unalterable.