This is a pendent, from one of my books called, "Tatsmithing: The Art of Silversmithing with String". A copy of it can be purchased from my Face Book Page: West Pine Creations. To the right of my blog, are links to information on my three books.
This pendent was made with two strands of Coats and Clark sewing thread. The stone was an ocular agate, shown as "bulls-eyes" or swirls. The swirls made a sort of a heart in the middle of this agate.