I spot checked several of your listings and my comment would be to work on your tags. Several of your one word tags are repeated in multiple word phrase tags which, as I understand it, is not necessary and is a waste of one of your tags. I would join a team that helps with SEO and work on your keywords. Then coordinate your tags with your titles and the first sentence or two of your description. You should use as many of your keywords in all three locations. Also, none of the listings I reviewed had tags relating to why someone would purchase your jewelry such as: gift, mother's day, birthday, etc. I would suggest you look at who your average buyer is and think about what phrase they might use in a search to find something - especially in relation to the reason to purchase.
Good luck - your jewelry is really unique.