Pleochroic halos are the result of crystal lattice damage due to the impact of alpha particles from radioactive decay occurring at the center of the halo. Halo identification is achieved through the measurement of the halo diameter. The size of the halo and the half-life of the isotope producing it are related. Assuming that the half-life of the parent isotope has remained constant throughout the formation of the halo, the initial energy of the alpha particles that produced the halos can be determined, and hence the parent radioactive isotope identified. In making this identification, Gentry assumes, as do other scientists, a constancy of radioactive decay rate for polonium.
All available data indicate that halo ring diameter increases with increase in decay rate.
Either the rates remain constant or they do not. Such inconsistency cannot be considered as a satisfactory argument. Questions 3 and 4 are the areas in which there is some of the most open contention between Gentry and other scientists, creationists and non-creationists alike. Throughout Creation's Tiny Mystery , Gentry claims that primordial poloniurn halos are found only in Precambrian granites, pegmatites and possibly some flood rocks. On the other hand, Gentry recognizes that the polonium halos in coalified wood are of secondary origin, i.e., due to transport into the wood of polonium derived from uranium, rather than arising by instantaneous fiat creation.