This appears to be a mixed metal piece since part is marked Alpaca (also called Mexican silver and is an alloy) and part is marked sterling. Beautifully designed with a slight curve on the links and they have inlaid turquoise chips in resin. 

• Size: 16" long. Bottom links are 1" long.
• Type: Pre Owned Retro Vintage from the 1980's.
• Condition: Slightly darkened patina. All inlaid areas are intact.
• Materials: Sterling silver, alpaca Mexican silver alloy, inlaid turquoise chips, resin.
• Markings: Marked 925 Sterling on the link by the hook clasp and Alpaca on the back of the first turquoise link on the bottom.
• Weight: Weight is 31.0 grams.