"Santa Rita de Casia, patroness saint of desperate cases, is almost always portrayed as she is here, with a spot of blood and a thorn deeply imbedded in her forehead. As the story goes, in the year of 1441, during a sermon on the crown of thorns, Santa Rita prayed so intently that a thorn detached itself from her crucifix and lodged itself in her forehead." link
This is the website of a lovely-looking store in San Francisco called Colonial Arts, located at 463 Union St. in the heart of North Beach, San Francisco.
The Art of Amy Crehore