About Us

The Mineral & Gem Society of Castro Valley was established in 1948 as a non-profit and educational organization.

We are a nonprofit educational organization dedicated to increasing public understanding of rocks, minerals, gemstones and the lapidary arts.

    All sales go towards keeping our shop doors open and funding our non-profit operations.

    We hold a General Meeting at 7:30 pm on the third Thursday of the month with the exception of July and August. It is held at the Church of Christ located at 22307 Montgomery Street (corner of Grace Street), Hayward, CA.  Members and non-members are all welcome at the general meeting. There will be door prizes and a silent auction. Look forward to seeing you there!