Does anyone know of any crystals that would be good for this practice? Any general advice? Spirits and deities are fairly obvious.
From what I’m reading, the crystals you need will depend on what you’re using necromancy for.
Archangel Azrael is perfect for guidance on necromancy. Anubis and Thoth will help as well.
Black obsidian has a strong connection and pull to the spirits of the dead, from what I understand.
My focal ring has a pyramid shaped piece of obsidian in it. It works rather well.