Identifying antique glass isn’t always easy. If you’re lucky, a piece may be marked, like this Phanomen vase, which is signed “Loetz Austria” on its pontil (the spot on the base where the blown molten glass was attached to a pontil for shaping).
Proof of its maker, not to mention its complex shape and silvery iridescent sheen, brought its price to $4,940 at a Rago/Wright auction. But glass isn’t al…