49 year old Madi Madi man.

I come from Balranald up on the Murrumbidgee River which is
part of the Great Willandra Basin where Lake Mungo
is situated. I'm sure we've all heard about the story of
Lake Mungo in recent years which pertains to the opalised skulls. 
Well, my bloodline comes from that country and I'm directly 
linked to those two skulls that were found in recent years.
Having said that, I have a question to pose to you, 
anyone watching this program: 'How long does it take for something
to opalise or turn into opal?' 
The significance of what I'm saying is history is important;
we've left our history and the makings of this earth here that is 
commonly known as Australia. 
We've found two opalised people, so the question is: 'How long 
does it take for Aboriginal people to turn into opal?'