"' Smaragdus'....a clear transparent Gem; very beautiful, and the most brittle of all Gems. It stops (being drunk) all Fluxes whatsoever, chiefly the Dysentery, whether they come from a sharp humor, or venome ; and it cures venomous Bitings. For a Dose—six, eight, or ten grains are given. Among Amulets it is chiefly commended against the Epilepsie; it stops bleeding if held in the mouth ; it cures all bleedings, and dysenteries ; it expels fears, and the Tertian Ague, if hung about the neck. There is a' Prepared Smaragd; and a Tincture of Smaragd.' "
If we turn our attention to the Online Etymology Dictionary, we find the following statement:
Sanskrit maragdam "emerald" is from the same source, as is Persian zumurrud, whence Turkish zümrüd, source of Russian izumrud "emerald." For the excrescent e-, see e-.
In early examples the word, like most other names of precious stones, is of vague meaning; the mediæval references to the stone are often based upon the descriptions given by classical writers of the smaragdus, the identity of which with our emerald is doubtful. [OED]Emerald Isle for "Ireland" is from 1795.
We can be certain that the Tibetan source of the term is Sanskrit. And it seems ultimately the Sanskrit term derives from the Greek. Interestingly, the Tibetans also identify a "stone" margad as malachite.
And this in turn raises the question— from what language is the name mu men (མུ་མེན)? This is the Tibetan name for lapis lazuli, a gem frequently misidentified as vaidurya by translators.