This anvil is made of a combination between mithral, platinum and melted obsidian, giving it a swirling marble like look. Around the rim of this anvil are sigils for multiple spells. When using this anvil by the blacksmith attuned to it, they can enchant the item they're crafting to contain spells that are marked on the anvil. The crafted item requires attunement to be able to use it to cast the spells. The spells can be cast once each as an action without expending a spell slot. The expended spells are recharged at dawn of each day. The type of material being used to craft the item affects how many spells and at what level can be enchanted on the item.
Bronze and iron - One spell up to 1st level. Requires enough material to make the item, plus 500gp (one pound) worth of residuum.
Electrum, Gold, Silver, cold iron and steel - Two Spells up to 1st level or one spell 2nd to 4th level. Requires enough material to make the item, plus 750gp (1 1/2 pounds) of residuum.
Adamantine, electrum, mithral and platinum. - Three spells up to 1st level, two level 2nd to 4th, and one level 5th to 6th. Requires enough material to make the item, plus 1500gp (three pounds) of residuum.
** It's up to the DM to decide what spells are on the anvil that can be used to enchant items.