Found only at the heart of the most ancient trees, dark wood is a potent magical substance. It is one of the few wood-based materials that is durable and potent enough to use in the construction of magical items. As such it is prized by artificers. Dark wood forms only in the mightiest of trees, primarily oak, hemlock, redwood, cypress, and beech, in center of the wildest and most pristine forests. It forms knots and swirls within the normal grain of its host, normally near the center of the trunk.
Much as a pearl forms in an oyster, dark wood forms in the heart of forest giants. Trees occasionally take up a particle of magical matter, mithril, orquelum, or lagra. The tree protects itself from this particle by forming a casing of dense wood around the irritant. This effectively traps the particle, which slowly transmutes the surrounding wood into dark wood. Over time the tree continues to layer wood over the magical energies within, forming more dark wood. A fist-sized knot of the precious substance could take three or four decades to form.
Finding dark wood is straightforward but time consuming. Appropriate trees can be identified using Good divination magic. The difficultly is in finding potential host trees. Dark wood only forms in undisturbed forest and the very act of seeking it out may disrupt its formation.
There are two ways to harvest dark wood. The destructive method is to simply cutting down the tree, removing any dark wood found. Using this method requires Great woodcraft and will disrupt any dark wood formation in the area for many years. Obviously it will also kill the host tree. The second method is to use nature magic and coax the tree into giving up its unwanted guest. This method is time consuming, requiring repeated visits to the tree as it slowly shifts the mass to the surface of its trunk. A month of daily visits, each involving a Good use of nature magic would normally be required to obtain a mass of dark wood in this way.
Once harvested it appears to be a dark, extremely fine-grained knot or root-like tangle of dense wood. Depending on the species of the original tree the wood may be brown, reddish, or almost black. Dark wood is faintly luminescent, giving off a faint purple glow.
Dark wood lends itself to several kinds of enchantment. It has a great affinity for nature and growth, and is prized as a material for magical bows. It is less suitable for other types of forms of weaponry. It's resilience allows it to be shaped into potent defensive magics.
Working with dark wood requires great skill. To properly discern the best use of a piece requires Great divination magic. Preparing it for use requires Superb wood crafting skill. Actually incorporating it into a magical item requires Superb enchanting skill.