Blue Signal carries its stones in three stations at the front of the chain. An oval sits on each side, and between them a slightly larger cushion with cut corners. Each stone is held by four prongs inside a raised frame ringed with small colorless zircons. The stations lie five or six links apart, so on the wrist all three rest across the top while the rest of the chain stays bare. That spacing makes it a station bracelet rather than a line of stones running all the way round. From above the links look like smooth silver domes; from the side they are hinged cups, which lets the chain bend and lie flat.

The blue centers are lab-created opal, grown rather than mined. They show the play of color that belongs to opal: flecks of turquoise and green move across a deep blue body as the wrist turns, and each stone has its own pattern. Some jewelers call this material synthetic opal. It is a different thing from opalite glass, which has an even milky glow and no play of color. Here each opal is set like a gemstone, in prongs inside its own halo, so this opal chain bracelet has nothing in common with a strand of glass beads.

The halos are natural zircon, a mineral in its own right and not cubic zirconia, the lab-made stone its name is often confused with. Colorless zircon is sold as white zircon, and it puts a bright white sparkle around each blue center. Zircon is a December birthstone, so the piece works as a December birthstone bracelet through its halos; the month comes from the zircons, not from the opal. It is a silver gemstone bracelet whose mined stones are the zircons, while the opals are grown.

Every link and setting is 925 sterling silver, not plating over another metal. The chain is cast and finished by hand in our workshop, then rhodium plated and polished to a white, mirror-like surface that slows tarnishing. At 7.5 grams it is a dainty silver bracelet, light enough for every day and slim enough to wear among sterling silver stacking bracelets or thin chains. It measures 21 cm, a little over 8 inches, and fastens with a box clasp. The tongue clicks into the box, and a figure-eight safety catch closes over it.

On the wrist it reads as a silver bracelet with blue stones and plenty of bright metal between them.