The Rhode Island-based jewelry maker Alex and Ani has purchased a winery in Little Compton. The jewelry company completed the purchase of the 170-acre Sakonnet Vineyards on Thursday. The real estate firm that sold the property said the price was $8.95 million. Alex and Ani president Carolyn Rafaelian has said the winery and the jewelry company make a ‘‘perfect pairing.’’ Rafaelian also purchased Newport’s largest privately owned mansion, Belcourt Castle, in November. The Cranston-based Alex and Ani has grown quickly since it was founded in 2004. Its products are made of recycled materials and are manufactured in the United States.