A silica crystal hangs like a lone piece in a game of jacks in a stereomicroscope image released in January 2009. Silica, one of the most common minerals on Earth, is the basis of sand and quartz, and is the primary ingredient in glass.
In geology, crystals have flat faces and linear edges, because crystalline structures are made from repeating units of highly ordered atoms--similar to building with Lego bricks. But in biology, proteins allow many animals to make crystals that have rounded edges.
Now a team of Spanish and Australian researchers has found that some minerals can form themselves into rounded crystal shapes without the aid of biological agents.
This means that structures that look like fossilized life trapped in stone may actually have formed when volcanic rocks came in contact with water on early Earth, the researchers say.
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Image courtesy Emilio Melero and Juan Manuel Garcia-Ruiz/Laboratorio de Estudios Cristalograficos (CSIC-Universidad de Granada)