Looks like a sandstone filled geode of some sort with the weathering causing the stone to erode away. You could help out by telling us where you found this, like at the beach in Daytona Fla. or Monterey. California.
Out of USA .
In a mountain was digging 60cm.
Do you know if you were in California or Colorado or the nearest city...?
What that mean?
Where in the world did you find it exactly. An answer would be...I found this on a mountain just outside of Berlin, Germany. That gives us your location when you found the stone.
looks like botryoidal fluorite