Abstract
Basic properties of domestic agate and of foreign agate were studied by an X-ray method, polarization microscope, thermal analysis and emmission spectrochemical analysis. The agate is a family of quartz with minute amount of Al and Fe or Mg ions as ingredients without any bonding materials such as amorphous glass or opal. The agate held a small amount of structural water which was eliminated off at the temperature ranging from 400°C to 600°C on heating. The values of thermal expansions of agate in principal axes, which were determined by high temperature X-ray diffractometer, were smaller than those of rock-crystal, especially in the direction of c axis. The agate transformed into cristobalite below 1025°C and the corresponding activation energy of crystal growth were evaluated to be about 60 kcal/mol. This value is smaller than that of siliceous stone. It was supposed that the broadning of five-fold lines in the vicinity of 68° in Cu Kα radiation, the broadning of α-β inversion peak in DTA curves, the structural water and the size of crystallites in agate were closely related to each other.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
