text: Seekers of these objects established a type of music known as fijri.
full_question: Seekers of these objects established a type of music known as fijri. One of these objects was nicknamed "LaPeregrina" because it frequently changed hands for nearly five hundred years. The momme, the Japanese unitof mass, is often used outside of Japan to measure the weight of these objects, which are retrieved by the amaof Okinawa. These objects have historically been a mainstay of Bahrain's economy. The delta region of a rivernamed for these objects is home to Hong Kong. The production of these objects at Sri Lanka's Gulf of Mannarinspired an opera by Georges Bizet. These objects are often composed of nacre. For 10 points, name thesevaluable objects produced inside oysters. 
first_sentence: Seekers of these objects established a type of music known as fijri.
raw_answer: pearls