We need details to help you. A pic just isn't enough with no information.
It appears to be metallic, but that's all I can gather from the pic. Melted metal chunks are common in burned down sites, so keep that in mind. The type of site found at could have a bearing on what it could be. Also, what was the VDI if you found it with a detector? Does it stick to a magnet?
Size won't help us identify it... but it is information to share.
