Interesting Stone/artifact

[Dor]

Interesting Stone found by my late uncle about 50 years ago.
found locally here in Israel ,in an area known to be rich with Cu so first glens it's seems like common Chrysocolla /Malachite , but the shape seems almost too perfect.
I am trying to figure if this stone was naturally made this way , or if possibly it's an ancient artifact which oxidized for many years? a cannon ball?
I thought first it's more dense but Sg shows only about 3-3.5...