A while back, a friend dropped this Mississippian Period blastoid in matrix off during his trip to Louisville. He had been collecting in the Indian Springs Formation of Crawford County, Indiana. The fossil is about as big as a marble.
So these first two pictures show the blastoid in the rock matrix. I decided to extract the blastoid with the Dremel engraver. The matrix was pretty soft and flaky.
I stopped to photograph the fossil plate with the engraver lines. Matrix has broken off revealing more of the blastoid theca.
Eventually the vibration of the engraver broke the blastoid free for its rock tomb. Now I need to sand blast it to reveal the top detail. Not the white marks where I probed to see if any more matrix would break away. Decided it might damage the fossil to proceed down this path.