“Be daring and have a little fun,” advises Kimberly McDonald, a New York-based jewelry curator and consultant who helps clients acquire their jewelry collections. “A comprehensive jewelry collection will offer diversity in scope and illustrate that the client has a sophisticated approach to her jewels.” McDonald herself favors the way designer Henry Dunay transforms large colorful gems such as a mandarin garnet into voluptuous pendants that serve as very personalized statements.

Indeed, it requires a collector possessed of blissful confidence and a strong dash of free spirit to feel comfortable dropping a half million dollars for a stone as elusive as a 9-carat electric blue paraiba tourmaline set in a ring. “[This] paraiba tourmaline is so beautiful that most people don’t know what to make of it when they see it,” says Andrea Hansen, director of marketing for H. Stern, the Brazilian-based jeweler with unrivaled access to its country’s rich gem supply. Most American clients, Hansen concedes, are not ready to spend that kind of money on an obscure gem, which is why H. Stern keeps the majority of its rare gem stash in its Brazilian stores. There, a mix of international travelers are more apt to spend the time and money to learn about unusual locally mined gems, then make significant purchases while visiting the region. Still, last year, an incomparable 7-carat alexandrite stone with a striking color change from green to red made its way to the New York boutique and sold for about $800,000. Hansen says it is possible that an alexandrite of that quality and size may never appear in the marketplace again.