Mineral Synthesis. 159 



mineral is not necessarily of one mctliod of origin, but may 

 be of very different methods, which can be determined. It 

 was not considered possible that a homogeneous magma could 

 at the same time give rise to different minerals. 



An envelope of mystery was thrown around the origin of 

 minerals, and they were regarded, even by Zirkel, as the 

 work of a kind of vital force. 



Many causes contributed to the rapid progress of the 

 science in the last twenty years; the strong prejudices of the 

 ancients are disappearing, observations and processes of in- 

 vestigation have acquired a remarkable precision, materials 

 and apparatus in the laboratories have been greatly improved. 

 When the new crystals were formed, they were found to be 

 small and often imperfect, not to be compared in beauty to 

 cabinet specimens, but far surpassing these in value in settling 

 questions of origin. They could not be properly studied 

 without the use of the microscope. Then it was found that 

 the minerals possessed inclusions, which threw much light 

 on the origin of the mineral. If these were vitreous, the 

 origin was vitreous, and excluded the action of volatile 

 agents ; when these are aqueous, the intervention of water is 

 ndisputable. Liquid carbonic acid, when found in minerals 

 like quartz, topaz, and beryl, give evidence of their formation 

 under great pressures. As mineralogical micrography was 

 developed, the varied order of consolidation of the different 

 minerals of rocks was discovered. The state of repose or 

 movement of the minerals during or after their consolidation 

 is manifested in the diversity of structure; such as zones of 

 growth, corrosions, flow structure and others. 



For example, micro-pegmatite on observation is found to 

 be an intimate mixture of quartz and orthoclase, thus proving 

 that two minerals can crystallize from the same magma at the 

 same time. 



In rocks, the mineral lencite is always formed before the 

 feldspar and pyroxene. As such rocks have an igneous 

 origin, it was regarded probable that lencite crystallized at a 

 temperature higher than that of the other silicate minerals. 

 This notion served as a guide in the reproduction of lencite 

 with its associated minerals. Then the observation of the 

 artificial product proved the assumption which served as the 

 point of departure. 



