You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Saint_Barth%C3%A9lemy

Context:
Saint Barthélemy, a volcanic island fully encircled by shallow reefs, has an area of 25 square kilometres (9.7 sq mi) and a population of 9,035 (Jan. 2011 estimate). Its capital is Gustavia[citation needed], which also contains the main harbour to the island. It is the only Caribbean island which was a Swedish colony for any significant length of time; Guadeloupe was under Swedish rule only briefly at the end of the Napoleonic Wars. Symbolism from the Swedish national arms, the Three Crowns, still appears in the island's coat of arms. The language, cuisine, and culture, however, are distinctly French. The island is a popular tourist destination during the winter holiday season, especially for the rich and famous during the Christmas and new year period.

Question:
What kind of island is St. Barts?

volcanic