When the doors swing open in early this month, there will be a lot that glimmers and shimmers inside Treasures by R.J. at 643 S.E. Jackson St. in downtown Roseburg.It's the first bricks-and-mortar jewelry store for owner Robin Gray and her husband, Todd, but they have been operating www.niceice.com, an online diamond brokerage for five years.Robin started Treasures by R.J. in California in 1979."We're a real good source for people who want diamonds of exceptional beauty, and of course we carry everything else related to jewelry," Todd Gray said. The store specializes in round brilliant ideal-cut diamonds, which represent "one-tenth …