I found two entries for John Boone (a John H. Boone and a John W. Boone) in the Civil War Soldiers and Saiors System for the 7th Va Cavalry (see http://www.itd.nps.gov/cwss/soldiers.cfm ) - of course they could be referneces to the same person but with a transcription error of the middle initial.

Their summary information on the 7th Va Cavalry :

7th Regiment, Virginia Cavalry (Ashby's)

7th Cavalry Regiment was organized during the late spring of 1861. In October authority was given to increase its size, and by the summer of 1862 the regiment contained twenty-nine companies. In June it was reduced to ten companies. Ten companies formed the 12th Regiment Virginia Cavalry, seven became the 17th Battalion Virginia Cavalry, one transferred to the 14th Regiment Virginia Cavalry, and one became J.W. Carter's Battery.

The unit served in W.E. Jones', Rosser's, and J. Dearing's Brigade in the Army of Northern Virginia. It took part in Jackson's Valley Campaign and the conflicts at Cedar Mountain, Second Manassas, Sharpsburg, Upperville, Fairfield, Bristoe, Mine Run, The Wilderness, Spotsylvania, and Cold Harbor. Later the regiment was involved in Early's Shenandoah Valley operations and disbanded in mid-April, 1865. None of its members were at Appomattox on April 9. The field officers were Colonels Turner Ashby, Richard H. Dulany, William E. Jones, and A.W. McDonald; Lieutenant Colonel Thomas Marshall; and Majors O.R. Funsten, Daniel C. Harcher, and Samuel B. Myers.