This is the twin of E.D. Marshall as you can tell. Identical mold and stamping pattern. My opinion is that Sandoval Jewelers is also from Arizona, somewhere around Scottsdale, where E.D. Marshall is still in business today. My theory is it was a friend and or relative of E.D. Marshall and they did bars in fairly limited quantity. These bars are high premium and particularly in 5 oz class. They are distinct with their square mold and really well done.
Vintage Silver Bars 