I made an oak computer desk for my son. Already had a file cabinet he wanted to match. It was very dark brown, nearly black. I had some Van Dyke Crystals I had gotten from Highland Hardware. Supposedly made from walnut husks. They extract the color and dry it to a powder. Mix it in water and you have a very dark stain. I used it and it appeared fine. Coated it with Sherwin Williams CAB Lacquer. My son taped the drawers shut with masking tape to keep my grandson out of it. When he pealed the tape off the finish, including the stain came off with it leaving the blond of the oak exposed.
Perhaps I should have put locks on the drawers.
Not sure what to make of the Van Dykes.