Wow and thanks a lot. If you didn't see this, here's how:

The condensed version.

I found a plastic Halloween mask at a TS and made a plaster mold of the mask.

Then I made a casting from the mold; the mix consisting of

1 part portland cement

2 parts pearlite

1 part redwood shavings(hamster bedding screened through 1/4" hardware cloth) The measure I used was a 38 oz coffee can.

When dry I painted it all green, (not the back)

http://s259.photobucket.com/albums/hh302/robertsbackyard/?start=60#!cpZZ1QQtppZZ8

I found a 14" plastic water tray (they go under potted plants) and made a casting of the tray (with the same mix as above), I embedded some wires in the front to join the face to and a metal support on the back,

The part cast from the tray measures 13 1/2" in diameter and is 2" thick, about the size of a large stepping stone.

I joined the face to the backing pieces with a 50 ~ 50 mix of Portland cement and water.

Then it was a matter of shaping it some, wire-brushing it some, and sanding it some before painting it all green, with acrylic paints, then dry brushing with gold, blue, purple, red, and yellow, spraying with transparent brown stain, and finally finishing with high gloss urethane.

http://www.the-artistic-garden.com/faux-painting-technique-verdigris.html

The completed piece weighs in at just over 5 pounds let's call it 6 pounds.

http://forums2.gardenweb.com/forums/load/hypertufa/msg042346082889.html?1

The completed piece weighs in at just over 5 pounds let's call it 6 pounds.The back is unfinished

That's all there is to it.

kinda looks like a big bottle cap.