The goddess Juno wore pearl earrings; the month of June is dedicated to her and the pearl is its birthstone. Known as the Queen of Gems, natural pearls are produced by the invasion of a minute parasite which is covered with nacre. Found in oyster beds they were so rare that only the noble and very rich could afford them. From ancient times they were associated with purity and peace but the life of the pearl hunter was difficult and dangerous. Alonso Sánchez Coello (1531-1588) was a Spanish Renaissance painter who pioneered the tradition of Spanish portrait painting. He became the court painter for Philip II of Spain where he painted the thirteen-year-old Infanta Isabella Clara Eugenia encrusted with pearls. Venetian Rococo painter Rosalba Carriera (1675-1757) was from the lower middle class and began her career doing miniature portraits on ivory for the lids of snuffboxes. She eventually became a popular portrait painter using the technique of pastel. The portrait of renowned Venetian beauty Caterina Sagredo Barbarigo is attributed to Carriera, it shows her wearing a single-strand pearl collar and pendant pearl earrings. The iridescence and luster of the pearl was also appealing to men especially the Maharajas of India. With the development of cultured pearls and pearl farming in the late nineteenth and early twentieth century the jewel became available to more people with less risk.