I have an amazing huge museum-quality silver and turquoise ring with the initials LB and the stamped symbol of a running horse. Would you please advise the name of the artisan? Thank you.

Not seeing a picture of the ring, I can't honestly tell. I did some more research on the web and found this source that has different Indian hallmarks listed from A to Z. Here is the link: Indian Native American hallmarks AL (http://www.art-amerindien.com/signature_bijoux_amerindiens.htm#l)

Hope this helps you out.
:)