Riverside Resources Inc. and Choice Gold Corp. have discovered gold in Arizona near the California border, Riverside said Thursday.

The partners, which are both based in Vancouver, found a new oxide gold zone at their Sugarloaf Peak Project, near Quartzsite, Ariz.

The shallow oxide portion at Sugarloaf Peak has identified favorable near surface mineralization and has expanded the potential for the project moving forward, said Riverside CEO John-Mark Staude.

Riverside holds 8.6 million shares of Choice Gold and stand to receive an additional 5 million shares over the course of an option agreement.

Riverside shares rose 12.8 percent in afternoon trading.