Spherulitic Recrystallization of Metamict Polycrase

Science  03 May 1974:
Vol. 184, Issue 4136, pp. 561-562
DOI: 10.1126/science.184.4136.561


Spherulites occur in the metamict matrix of the rare earth AB2A6- type niobium-tantalum-titanium oxide, polycrase. Microprobe analyses show that the spherulites are similar in composition to the metamict polycrase except for a fivefold increase in calcium oxide. X-ray examination suggests that the spherulites are a titanium-rich rare earth fersmite.