| The transitions between low and high leucite and between ;Following Van Tendeloo et al. (1976 Phys Sat Sol 33:723), we observed the dispersal of Dauphine twins into an ordered, incommensurate structure at the ;Examination of the microstructures in the fibrous quartz of agates suggests that chalcedony is structurally distinct from bulk ;Jaspery and sideritic spherulites from Precambrian banded iron formations were examined for evidence of biogenicity. Analysis of the jaspery spheres suggests a purely diagenetic origin, whereas the sideritic spheres were found to have cores of apatite. Though the source of the phosphorus may have been biological, the abundance of phosphorus would indicate that they do not represent fossilized cells per se. |
