A horse registered with AQHA which is the result of breeding a Thoroughbred and an American Quarter Horse that has a permanent number, or a combination of an Appendix numbered American Quarter Horse and an American Quarter Horse with a permanent number. Appendix horses are distinguished by an "X" in front of their registration number and their certificates are gold.
There are three different mixes of horses that are eligible to be registered in AQHA's registry:
1. Registered Appendix (X) + Registered American Quarter Horse (QH) ' Registered Appendix foal(X)
2. Registered American Quarter Horse (QH) + Registered American Quarter Horse (QH) ' Registered American Quarter Horse foal (QH)
3. Recognized Thoroughbred (TB) + Registered American Quarter Horse (QH) ' Registered Appendix foal (X)
There are 13 recognized colors for American Quarter Horses. Bay, Black, Brown, Sorrel, Chestnut, Dun, Buckskin, Red Dun, Grullo, Palomino, Gray, Red Roan, Blue Roan.
A horse registered with AQHA which is the result of breeding a Thoroughbred and an American Quarter Horse that has a permanent number, or a combination of an Appendix numbered American Quarter Horse and an American Quarter Horse with a permanent number. Appendix horses are distinguished by an "X" in front of their registration number and their certificates are gold.