I can pick up the diamonds without too much straining, they are more bulky and awkward to handle than they are heavy. If I had to guess, the mdf diamond might weigh about 60 lbs. I am about to load up two pictures of another diamond which was made from thicker plywood. That one might be about 80 lbs.

Hopefully there won't be any theft, it'd be hard to justify the value to my insurance!