How to determine value of inherited mineral rights in 2007?

Inherited mineral rights to Madera 26-76 in Loving County, Texas in 2007. Now I’m trying to pull off a last-minute tax filing with no idea how to determine the value. Sold my part of mineral rights in 2017.

Need to have some idea / formula by Oct 15th!!! Would greatly appreciate any input anyone has.

If you have a copy of the estate tax return, then the value would be stated. In 2007, the minerals had a very small value relative to 2017. Most of your sales price will be long-term capital gains.

Thank you for your reply. The estate attorney for my parents never did give my sister and me the estate tax returns back after my mom’s passing in 2006. I knew the minerals back in 2007 were not worth that much. What is a ballpark amount that Madera 26-76 Loving County might have been worth then? I just need an approximate value.