In Hooks v. Neill, 21 S.W.2d 532, 538 (Tex. Civ. App.--Galveston 1929, writ ref'd), the grantor owned and conveyed all of his undivided 1/2 interest in a tract of land. 21 S.W.2d at 538.
The grantor reserved a 1/32 interest in oil under the "said land and premises herein described and conveyed." Id.
The court focused on the words "and conveyed" and held that the deed unambiguously reserved 1/32 of the 1/2 minerals that the grantor conveyed, or a 1/64 mineral interest. Id.