Eudialyte

Amazing Story!

Almost simultaneously, mineral specialists at the Canadian Museum of Nature and at the University of Copenhagen noted unusual differences in the X-ray patterns of various eudialyte specimens in their respective collections. To investigate these anomalies further, staff of both institutions decided to sample a large number of eudialyte specimens from around the world and to chemically analyze them with the museum's electron microprobe. To our surprise, there was a wide variation in chemistry in the 60 samples that we analyzed. In fact, we saw so many possibilities of elements substituting for other elements in the structure that we routinely had to analyze for 46 different elements. This was not going to be an easy study! To fully understand the crystal structure of eudialyte, a large number of structure analyses would have to be performed. The solution came slowly, over several years, but we now have an excellent understanding of the complexities of the eudialyte structure.

You may ask why it is important to spend so much time on this relatively rare mineral. Eudialyte is an important source of zirconium, a rare element that is normally found in complex silicates. The term "rare element" implies that a particular element is not abundant in the earth's crust in comparison to common and familiar elements such as silicon or oxygen. While zirconium is only number 18 in terms of abundance, it is very widely dispersed and can be considered rare. Zirconium is used in the production of synthetic fibres; in construction materials for aircraft, space vehicles and rockets; in fabrication of fuel-element cans for atomic reactors and in the manufacture of super-hard alloys. The complexity of eudialyte's structure makes the recovery and concentration of zirconium difficult. Understanding how such elements are bonded in the structure facilitates their extraction.

Because of its complex structure, eudialyte can also host many other rare elements. The presence and distribution of these other elements can tell scientists much about the nature and conditions of the crystallization of the magma (molten rock) in which the eudialyte formed.

This study has resulted in the description of four new members of the eudialyte group, and the search continues. In 1999, a joint CMN-University of Copenhagen field trip to an isolated part of east Greenland where more alkaline rock has been reported may result in the discovery of more eudialyte.