A-Mark - is that one of those little chunky ones? Saw a guy on Kitco had an ammo tin with 500 of them in it! Think he also had pictures where he'd used them like Lego blocks to make a fort
Chunky yes. 32 x 21 x 6 mm. It does look like it would stack quite successfuly as the base is slightly larger than the top with a small lip.