stones of an inferior quality are brought from the Fichtelgebirge in Bavaria, and are sold as ‘Hungarian cat’s-eyes,’ despite the fact that no such stone occurs in Hungary—another instance of jewellers’ disdain for accuracy. Tiger’s-eye occurs in considerable quantity in the neighbourhood of Griquatown, Griqualand West, South Africa. A silicified crocidolite, in which the blue colour is retained, comes also from Salzburg, and is known as sapphire- or azure-quartz, or siderite. Certain of the pebbles found on the seashore of our coasts, especially off the Isle of Wight and North Wales, cut into attractive, clear stones, more or less yellow in colour; but examples suitable for the purpose are not so numerous as might be supposed, and do not reward any casual search. _Les affaires sont les affaires._ The local lapidary, instead of explaining that the pebbles brought to him are not worth cutting, finds it more convenient and profitable to substitute for them other, inferior and badly cut, stones, bought by the gross, or even paste stones; the customer, on the other hand, is contented with a pretty bauble, and is not grateful for the information that it might have been obtained for a fraction of the sum paid. CHAPTER XXIX CHALCEDONY, AGATE, ETC. Chalcedony and agate, and their endless varieties, are composed mainly of silica, but the separate individual crystals are so small as to be invisible to the unaided eyesight, and occasionally are so extremely minute that the structure is almost amorphous. The colour and appearance vary greatly, depending upon the impurities contained in the stone, and, since both have been made a criterion for differentiation of types, a host of names have come into use, none of which are susceptible of strict definition. On the whole, these stones may be divided into two groups: chalcedony, in which the structure is concretionary and the colour comparatively uniform, and agate, in which the arrangement takes the form of bands, varying greatly in tint and colour. The refraction, though double in the individual, is irregular over the stone as a whole, and the indices approximate to 1·550. The specific gravity ranges from 2·62 to 2·64, depending upon the impurities present. The degree of hardness is about the same as that of quartz, namely, 7 on Mohs’s scale. All kinds are more or less porous, and stones of a dull colour are therefore artificially tinted after being worked.