These are Dark Gray Labradorite Oval shaped 6mm beads with blue flash. These look like black opal. They are strung on thread and measure about 13" in length and approximetly 33 beads to the strand. The beads measure on average 6mm. They are native cut so there are some differences in shape and size. This is the last strand I have and I did not count the 2 broken beads on the strand in the above stated total. These are great for that organic look. Feel free to e-mail me with questions.