Lost family heirloom necklace (marina / cow hollow)

On my run on Monday or Tuesday, I lost a necklace that is really important to myself and my family (photo below). I ran through the presidio, along Marina boulevard, by the beach, and through the Marina / near Chestnut Street. I have included a photo of both the necklace, and the two routes I was running on where it may have fallen. I would be so grateful if you find it / happily will pay a reward if found.