Tex. Nat. Res. Code § 31.1582
(a) If the General Land Office receives from a landowner an offer to buy the state's interest in the mineral estate in real property to which the landowner holds title, the General Land Office may sell to the landowner, for fair market value, any fractional mineral interest held by the state that:
(2) is severed from a parcel of land that:
Added by Acts 2007, 80th Leg., R.S., Ch. 491 (S.B. 214), Sec. 1, eff. June 16, 2007.