1. In a medium saucepan, combine chicken stock and butter; bring to a boil over medium-high heat. Add both rices and 1/2 teaspoon salt; reduce heat to a simmer, cover, and cook, until liquid is absorbed and rice is cooked through, about 50 minutes. Remove from heat and let stand, covered, for 5 minutes. Uncover and fluff rice with a fork.

2. Transfer rice to a large bowl. Add dried fruit, almonds, orange juice and zest, olive oil, vinegar, remaining teaspoon salt, and pepper; toss to combine. Let stand 10 minutes before serving.