The metal needs to be tested somehow; it can't be identified from a photograph.
The definitive test would be from someone with an X-ray fluorescence (XRF) unit. The "old-fashioned" ways are with an electronic metal tester, a precious metal testing kit of acids, or with plain old nitric acid. A torch test may be further needed if platinum is suspected. The easiest quick check is with a rare earth (or very strong regular) magnet, but that is not definitive.
ID bracelets are seldom done in expensive precious metals, but that does have a different kind of adjustable clasp; not the regular Speidel type catch. Precious metal jewelry is also usually stamped with the manufacturer and the metal. Also check to see if the links are soldered or just pinched together. Speidel category ID bracelets always just had pinched together links, but again, this is just an indicator and not definitive.
Hope this helps and good luck!
