No. 101: Sep-Oct 1995
Diamonds as gems have an eerie hold on the human mind. Scientists, too, find them mysterious in several ways. Despite considerable study, the origin(s) of diamonds remain controversial. In SF#92*, we already mentioned and illustrated the unusual orthogonal arrays of hollow tubes discerned in some diamonds at high magnifications (100X). These tubes remain unexplained, as far as we know.
Now, in some diamonds, these tubular arrays are found to be associated with radiohalos. Radiohalos are often seen in some common minerals, such as biotite, but, even there, questions of origin persist. (See SF#25 and SF#58.) No one questions that radiohalos, whether in biotite or diamonds, arise from the the decay of radioactive inclusions; that is, mineral specks carrying uranium, thorium, or some other radioactive element. But how did these radioactive specks get lodged inside the hollow tubes which themselves are encased within diamonds? The problem is that these specks have much lower melting points than the diamond matrix. Why wasn't the liquid radioactive material dispersed throughout the higher melting point diamond matrix long before the latter crystallized? The same question must be asked about the radiohalos themselves, because the application of heat quickly anneals and disperses them. Complicating the picture still further is the fact that some of the radiohalos arise from the decay of polonium-210, which has a half life of only 138 days.
The hollow tubes, the lowmeltingpoint inclusions, and shorthalflife radiohalos combine complicate the explanation of diamond origin(s) and geological history. (Armitage, Mark; "Internal Radiohalos in a Diamond," Creation Ex Nihilo Technical Journal, 9:93, 1995. This creationist journal is published in Australia. The article is based mainly on: Mendelssohn, M.J. et al; "Internal Radioactive Haloes in Diamonds," Diamond Research, 17:2, 1979.)
Comment. Explanations of the forgoing conundrums hypothesize the invasion of crystals by impurities after diamond solidification.
*SF#92 = Science Frontiers #92.