The names in popular use for the principal gem-stones may be traced back to very early times, and, since they were applied long before the determinative study of minerals had become a science, their significance has varied at different dates, and is even now far from precise. No ambiguity or confusion could arise if jewellers made use of the scientific names for the species, but most of them are unknown or at least unfamiliar to those unversed in mineralogy, and to banish old-established names is undesirable, even if the task were not hopeless. The name selected for a gem-stone may have a very important bearing on its fortunes. When the love-sick Juliet queried ‘What’s in a name?’ her mind was wandering far from jewels; for them a name is everything. The beautiful red stones that accompany the diamond in South Africa were almost a drug in the market under their proper title—garnet, but command a ready sale under the misnomer ‘Cape-ruby.’ To many minds there is a subtle satisfaction in the possession of a stone which is assumed to be a sort of ruby that would be destroyed by the knowledge that the stone really belonged to the cinderella species of gem-stones—the despised garnet. For similar reasons it was deemed advisable to offer the lustrous green garnet found some thirty and odd years ago in the Ural Mountains as ‘olivine,’ not a happy choice since their colour is grass- rather than olive-green, apart from the fact that the term is in general use in science for the species known in jewellery as peridot. The names employed in jewellery are largely based upon the colour, the least reliable from a determinative point of view of all the physical characters of gem-stones. Qualifying terms are employed to distinguish stones of obviously different hardness. ‘Oriental’ distinguishes varieties of corundum, but does not imply that they necessarily came from the East; the finest gem-stones originally reached Europe by that road, and the hardest coloured stones consequently received that term of distinction.