Ruby is a variety of the mineral corundum, which is the hardest gem mineral after diamond. Small amounts of chromium in corundum give rubies their rich redness. They also cause a red fluorescence which further enhances the colour.
This ring forms part of a collection of 154 gems bequeathed to the V&A by the Reverend Chauncy Hare Townshend, a cleric and poet. Sir A. H. Church gave additional specimens in 1913. He also compiled the first catalogue Precious Stones: A Guide to the Townshend Collection. The first edition appeared in 1883. The stones are mounted as rings, although they may not have been intended to be worn.