Is it even possible to dissolve a limestone matrix without damage to the calcite fossil covered by it? Is there a solution strength that would not affect calcite yet would be able to loosen or dissolve attached limestone? My objective is in fossil preparation, being unsuccessful in my search to find an appropriate chemical or acid concentration that won't do damage to calcite fossil such as a crinoid from the Middle Devonian era. Muriatic 6%, vinegar, even Sno-Bowl commercial cleaners all damage both the calcite and the surrounding limestone no matter how thin the limestone layer. Shale cleaners such as the Larry Osterberger solution, RockQuat, etc. do no damage to calcite or silica fossils but is ineffective on limestone. Any suggestions?

Hum ... limestone is to a large extent calcium carbonate, so I think mechanically removing the limestone would be the better solution.

Hum ... limestone is to a large extent calcium carbonate, so I think mechanically removing the limestone would be the better solution.

 

What he said. If acid worked, they'd have been doing it for years. The fossil and matrix are for the most part identical chemically so mechanical removal is the only way to not ruin what you're after.