The three pillars in black onyx

The same puzzle as our wooden piece of the same name, with every wooden part cut from black onyx instead. Each part is shaped from one piece of stone, polished by hand, and every edge and corner is rounded so the stone does not chip where the cord pulls across it.

Black onyx is a fine-grained quartz polished to a deep, even black. At 6.5 to 7 on the hardness scale, everyday handling does not scratch it.

The cord and the steel ring are the same as on the wooden piece, so the solution is the same. We can cut it in rose quartz, amethyst, nephrite jade, lapis lazuli, black onyx, red jasper, tiger’s eye or smoky quartz.