The Vintage 5/8"+ M.F. Christensen and Sons BRICK is a rare and collectible marble from the pre-1970 era. Made by Christensen Agate, a renowned brand in the marble industry, this machine-made marble features a swirl pattern, adding to its unique and classic style. With a length of 9 and a long tail, this marble is a sought-after piece for toy and hobby enthusiasts looking to add a piece of history to their collection.