Here are two different styles of chess rook. Not part of a set, these pieces were only intended to be trinkets. However, I am considering making complete sets to match.

The first rook is a fairly traditional design with some added brickwork detail. It has a hollow centre to reduce it's volume, which can also be used to glue in a magnet. It's dimensions are 25x50mm and it has a volume of 14.7ml.

The second is a double helix design. It also has a hollow base and the same top section. It's dimensions are also 25x50mm and it has a volume of 10.7ml.