standing block stability

Quoted text begins.Should such a block sit on a special base anyway?
End of quote.

Norman, I'm not an engineer, but I cringe at the thought of someone laying under
this stone after it has toppled. It would ruin their day, and yours - you should
take all precautions against this happening.

Draw a scaled side view of the standing block. Divide the vertical face into
three equal, vertical parts. Locate the centre of mass, and draw a line down
through the bottom of the block. When the block is tipped - something like 4"
horizontally - so that the vertical line travels outside the middle third part,
the block will be at its point of balance.

Ideally, you should consult an engineer to cover all possibilities. An engineer
may suggest dowelling the block into a massive, concrete Tee-section footing.

If you weren't too worried, then you could just place the block on the ground,
then dig under one corner at a time and pour concrete to fill each hole
separately. This is a risky method, however because the block could fall over
while the holes are being dug.

Simon