Science reveals: a 100 year old mystery is solved ; Technion Scientists found that “vaterite” crystals are composed of two different atomic arrangements

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“Vaterite” is an unstable atomic arrangement of “calcium carbonate”

Technion scientists solved the 100 year old mystery when they discovered that “vaterite” crystals are composed of two different atomic structures. This was revealed in the prestigious scientific journal, “Science” .

Assistant Professor Boaz Pokroy and his doctoral student Lee Kabalah-Amitai from the Department of Materials Science and Engineering, explain that calcium carbonate, a compound of calcium carbonate and oxygen, is the most abundant mineral in nature, and appears in different forms that vary in their spatial atomic positioning (atomic arrangement). “Vaterite” is a specific atomic arrangement of “calcium carbonate” and in relation to other atomic arrangements, is extremely rare (in nature). Although it is not very uncommon, “vaterites” are present in many aspects of our lives.  For example, it can appear as gallbladder stones, can be found in certain geological structures, used as an essential material for the paper industry, an important constituent of cement, and even found in meteorites from space.  Scientists from the Technion are studying the development and formation of vaterits in the important biological process known as Biomineralization. In this process, living organisms control the production of different minerals on its atomic level. For example, when a mollusk shell receives a blow that cracks its shell it uses “vaterite” to repair the damage, a pearl usually has a deep shine (resulting from a collection of different calcium carbonate) but occasionally (as a result of a growth error) vaterite forms in the pearl and eliminates its shine, and fish (such as salmon) grow vaterite in their ears to aid them with their balance.

For over 100 years, scientists have failed to reach a clear cut explanation for the atomic arrangement of “vaterite”. Doctoral student Lee Kabalah-Amitai, with the guidance of Assistant Professor Pokroy, studied this topic by examining crystals found on  and within the bodies of small marine animals (from the Tunicate family also known as sea squirts) called “Hardomia momos”, with help from Boaz Mayzel, a sea biologist and scuba diver from the Tel-Aviv University who collected the specimens, Dr. Yaron Kaufman, who examined materials under the Technion’s “Titan” electron microscope (the only one of its kind in Israel), and assistance by Dr. Andy Fitch, a scientist at the synchrotron in  Grenoble, Leonid Bloch from the team of Assistant Professor Pokroy, and Professor Pupa Gilbert from the University of Wisconsin-Madison.

“This small organism produces a bundle of crystals from “vaterite” that are very sharp and relatively large, making them relatively easy to work with”, explains Pokroy and Lee Kabalah-Amitai. “This is why we examined these crystals; and this is the first time they have ever been studied on the atomic level. Until now, different scientists tried to find a unified atomic arrangement for vaterites or determine which of its original structures were the most accurate. We found that vaterites actually consisted of two different atomic arrangements that exist in harmony with one another. The second atomic arrangement was found in a microscopic area (nano-metric – around 40,000 times smaller than a human hair) and this is the reason it eluded the eyes of scientists who believed this was a singular structure rather than a dual structure.”

Vaterite is an unstable atomic structure, making it a rare formation in nature.  Nonetheless, it can still be found in different areas. Technion scientists expect that their discovery will facilitate future understanding of the formation mechanisms and stabilization of “vaterite”.

Above: Spicule made of vaterite crystals that were removed from the “Hardomia momos