Greg Retallack was one of those involved in the search.
He concentrated his efforts in Antarctica.
There was definitely a missing piece to this whole thing,
and we struggled with, to find out what that was and the clue was in front of us actually for quite some time.
In the middle 1990s, he led an expedition to see what was there.
It was really the trip of a lifetime and it was something I'd wanted to do for about 15 years before.
The team spent weeks exploring the Permian rocks,
but one bed of rock in particular attracted his attention.
We knew it was the very latest Permian bed,
and inside that bed there were quartz grains that had some very unusual features.
Quartz is the most common crystal on earth.
It's most frequently white and translucent.
Most of the quartz is just like this grain that I'm on now and it's a very clear grain.
Looking through the microscope, the light shines through it brightly, it looks white.
But some of these crystals weren't white or clear.