dense

Thanks in advance for any input and opinion on what this may be. I found this while landscaping laying mulch, as we were emptying a trailer load of it into wheelbarrows. I heard a "ding" on my shovel and immediately investigated only to find this oddly intriguing stone. ~7cm^3 volume : 54g...

I found this neat gemstone set in some kind of metal on the sidewalk. It is very heavy for it's size. Any thoughts on it would be great. Thanks,