This is quite late, sorry. I just decided to revive my Stone of the Sign entries from my newsletter archives.
According to tradition, the Zodiacal sign Cancer (June 21 to July 22) belongs to the water element and rules imagination, sensitivity and the all activities related to motherhood and nurture. Cancer is ruled by the Moon and moonstone, pearl, shell and milky stones are all in tune with her. Wearing any of these during her time or to support any of her activities will help you to align with her energy. The following are examples of Cancer stones. The blue nautilus is still available in my Etsy Store and I have a pretty moonstone that I could wrap for you if you would like.