Slate table with metal bowl insert

The table has a stone/slate top with a metal bowl in the center. The bowl has handles and can be lifted out easily and came with two tools of the same material. The base is made of metal and wood. I aquire it from a real estate agent who was emptying a home for showing. The owner had passed and nobody knows it's age or where it came from. I have some suspicions about it use and purpose but would like to know more about it. It's an interesting piece people see as soon as they enter my home and when they ask me about it I have nothing really to say.