Gems Notes and Extracts Augusto Castellani, Mrs. John Brogden 1871

16 GEMS.demand for them varying, cause also a change in thevalue at different times attributed to them. We shall,therefore, following the example of many other writers,adopt the alphabetical order* as the most simple, convenient,and useful to those who wish to study thissubject, although perhaps it is the least scientific in amineralogical point of view. But we wish it to beunderstood that this work is not a strictly scientifictreatise so much as a collection of useful and curiousnotes about all sorts of precious stones.* This order cannot be observed in the translation, the initialletters of some gems being different in English.