Experts from the VS Sobolev Institute of Geology and Mineralogy (IGM) SB RAS in Novosibirsk have successfully reproduced in the laboratory a co crystallization process for diamond and garnet that mirrors the way these stones form in nature. The findings were shared with socialbites.ca through the press service of the Russian Science Foundation, which supported the research.
Researchers designed a simulated mantle environment using a high pressure apparatus of the truncated sphere type. This setup creates the crushing pressures that Earth’s mantle experiences at a depth near 200 kilometers, roughly 65 thousand atmospheres, while heating the specimens to temperatures between 950 and 1550 degrees Celsius. The goal was to observe, in controlled conditions, how carbon bearing fluids interact with mineral phases to yield diamond and garnet crystals in tandem.
The experimental assembly consisted of garnet samples, tiny diamond seed crystals about half a millimeter in size, graphite, and either silver oxalate or oxalic acid. These compounds act as a liquid carbon dioxide and hydrocarbon source under laboratory conditions, enabling a dynamic carbon environment during the run. After a four day run, the team carefully examined the newly formed minerals to determine their structure and chemical makeup.
Results showed that the growth of diamond and garnet is driven by the interaction of garnet with carbon dioxide and hydrocarbon liquids that are present in the system. The scientists observed that the diamond growth rate varied with temperature, ranging from about 0.013 to 0.8 micrometers per hour depending on the exact thermal conditions.
From the measured growth rates, estimates indicate that producing a gemstone weighing one carat (approximately 0.2 grams) would take between about four and a half months and up to nearly seventeen and a half years in this laboratory scenario. By comparison, the record scale gem Kulian, weighing 3,106.7 carats (621 grams), would require an interval spanning from decades to several millennia in nature when formed through natural processes. Such calculations help illuminate the realistic timeframes involved in deep earth crystallization and underscore the immense timescales of natural diamond formation.
The researchers explain that the outcomes offer new insights into the conditions under which diamond bearing rocks originate and the potential role garnet plays in guiding diamond crystallization. These data contribute to the development of modern models for natural diamond formation and advance the understanding of how different growth environments influence final mineral properties. The team envisions future studies aimed at linking specific growth conditions with the physical characteristics of diamond, including texture and impurity content, to better reconstruct how diamonds form in the Earth’s interior. The findings are part of ongoing experimental mineralogy and crystallogenesis programs at the Institute of Geology and Mineralogy and are presented as a step toward more accurate geochemical models of mantle processes. Attribution: Institute of Geology and Mineralogy, Russian Academy of Sciences.
In parallel scientific developments, Russian researchers previously explored cosmic phenomena related to particles carrying extraordinary energies, further illustrating the breadth of experimental approaches used to understand materials under extreme conditions.