There may be more kinds of stuff in nature than was believed, U.S. researchers say, describing a new category of solids neither pure glasses nor crystals.

"Very weird," materials physicist Lyle Levine of the National Institute of Standards and Technology said. "Strangest material I ever saw."

Levine is part of a U.S-French team reporting an analysis of a solid alloy they discovered in small discrete patches of a rapidly cooled mixture of aluminum, iron and silicon.

The material appears to have none of the extended ordering of atoms found in crystals, which would make it a glass, except it has a very defined composition and grows outward from "seeds" -- things that glasses most assuredly do not do, an NIST release reported Thursday.

Crystals fill up space with atoms or molecules in specific, fairly rigid patterns that are symmetrical in any direction, while glasses have no symmetry and are just a random arrangement of their components.

The new material, which the research team has dubbed a "q-glass," can be shown by X-ray diffraction to have no symmetry, just like a glass, and yet the atomic arrangement apparently is not random, Levine said.

Seen under a microscope, q-glass regions grow outward from a seed during cooling and exclude atoms that don't fit.

"It's rejecting atoms that aren't fitting into the structure, and if there's no structure, it's not going to be doing that," says Levine. "It's amazing. Everything you can think about this thing behaves like a crystal, except it isn't."

One possibility, he said, is that the q-glass is the first example of a 3-dimensionally ordered configuration of atoms that nevertheless possesses no symmetry.

"Such structures have been theorized by mathematicians, but never before observed in nature," he said.