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

9.6.EPILOGUE. 235out a lengthened dissertation on the goldsmith's art,which would have caused us to deviate from theprincipal subject. Besides, this subject has alreadybeen treated by me in a short work entitled DelTOreficeria antica, and perhaps will be again consideredin a more voluminous work.The genera of the third class, to which belong almostall the substances called gems, are, as stated in theintroduction, twenty-four; but we need not namethem all, those being sufficient which include everysubstance partaking of the nature and name of preciousstones.All gems, then, are arranged under the followinggenera and orders of the third mineralogical class :The 1st.6th.7th.8th.9th.Non-metallic oxides.Aluminates.Aluminous silicates.Non-aluminous silicates.Silicates mixed with other components.To the first genus, of non-metallic oxides, belong thespecies1st. Of corundum, some of whose varieties are :1 . The oriental ruby.5. The oriental amethyst.2. The oriental sapphire.IThe oriental emerald.3. The oriental aqua- 7. The oriental topaz.marine. 8. The adamantine spar.4. The oriental alaban-:Emery.dine. 10. The oriental jacinth.