What would be the job of a theoretical wizard with the name _____ the Smaragdine?
Crystalline the Smaragdine, is a little-known Elven Wizard, and the guardian of powers of Morale & Healing in all gemstones & crystals of Middle-earth. She is dedicated to oversee that these powers are available to all races & beings who wish to use them for good only, never evil. (She is a friend of Galadriel's & lives in Lothlórien; she also makes Elven-jewelry.) 
[Of Note]: It is said that Celebrimbor had secretly forged a fourth Ring, which would have been the "Ring of Earth", made of mithril and set with an emerald stone. It would have been called "Cemenya" (derived from the Quenya word 'Cemen', meaning earth). This ring would have been worn by Crystalline at some point, and would possess the powers of Healing & Rejuvenation. It's whereabouts would still remain hidden.
ALTHOUGH! ...there is a legend among Hobbits, about sightings of a Green-'glowing' Neekerbreeker who may have eaten such a ring, which was lost in the Midgewater Marshes long ago, about the Third Age. And, given that the Rings had "the power to grant a lifespan far beyond a natural mortal one", it is likely that this unique creature still lives! ...So, keep an eye out for the one & only "Emerald Neekerbreeker" ...if you can find it.
“Some believe it is only great power that can hold evil in check, but that is not what I have found. It is the small everyday deeds of ordinary folk that keep the darkness at bay; Small acts of kindness and love. Why Bilbo Baggins? Perhaps because I am afraid, and he gives me courage.” ~J.R.R. Tolkien