Mysterious Quasicrystals May Have Fallen From Space, Study Says - International Business Times

A new study indicates that quasicrystals, a type of mineral once thought to be "impossible" in nature, is of extraterrestrial origin and probably around 4.5 billion years old.

Found in Russia's Koryak mountains,the quasicrystals may have fallen to Earth from space, according to a new study published this week in the Proceedings of the National Academy of Sciences.

The crystals had only been created in laboratories before geologists found them entertwined with a silica mineral that forms only at high pressures, and might have been created by a collision with chondrite body.

Scientists say that unlike conventional crystals, quasicrystals contain mathematically regular but unique units that never appear twice, unlike regular crystals which are made up of regular, repeating units.

Quasicrystals first became known to science in early 1980s when researcher Daniel Shechtman created them in his laboratory. Since then scientists replicated Schechtman's findings in labs.

Two years ago, a fragment of rock from Russia's Koryak mountains which because the first example of a naturally-occuring quasicrystal.

A team of researchers carried out an analysis of the sample based on the theory that the quasicrystal is part of a meteorite that fell to Earth.

According to a New Scientist report, the researchers say "the rock has experienced the extreme pressures and temperatures typical of the high-speed collisions that produce meteoroids in the asteroid belt."

In addition, the relative abundances of different oxygen isotopes in the rock matched those of other meteorites rather than the isotope levels of rocks from Earth, the report said.

The scientists added that the pattern of oxygen isotopes are typical of ancient meteorites called carnonaceous chondrites, which were formed at the birth of the Solar System, making the quasicrystal around 4.5 billion years old.

The findnigs of theoretical physicist Paul Steinhardt's study, who spent weeks tracing the origins of the world's only known natural example of a quasicrystal, was published in the Proceedings of the National Academy of Sciences.

Superhard, amorphous diamond created

The Tiffany Yellow Diamond

An amorphous diamond, one that lacks the crystalline structure of diamond, but is every bit as hard, has been created by a Stanford-led team of researchers.

What good is an amorphous diamond?

“Sometimes amorphous forms of a material can have advantages over crystalline forms,” said Yu Lin, a Stanford graduate student involved in the research.

The biggest drawback with using diamond for purposes other than jewelry is that even though it is the hardest material known, its crystalline structure contains planes of weakness.

Those planes are what allow diamond cutters to cleave all the facets that help give a diamond its dazzle – they are actually breaking the gem along weak planes, not cutting it.

“With diamond, the strength depends on the direction a lot. It’s not a bad property, necessarily, but it is limiting,” said Wendy Mao, the Stanford mineral physicist who led the research. “But if diamond is amorphous, it may have the same strength in all directions.”

That uniform super-hardness, combined with the light weight that is characteristic of all forms of carbon, including the diamond, could open up exciting areas of application, such as cutting tools and wear-resistant parts for all kinds of transportation.

Other researchers have tried to create diamond-like amorphous carbon, but have only been able to make extremely thin films that contain impurities such as hydrogen and do not have completely diamond-like atomic bonds.

The amorphous diamond created by Mao and Lin can be made in thicker bulk forms, opening up more potential applications.

The researchers, seen here, created the new, super-hard form of carbon using a high-pressure device called a diamond anvil cell.

They did a series of experiments with tiny spheres of glassy carbon, an amorphous form of carbon which they compressed between the two diamond anvils.

The spheres were a few tens of micrometers (millionths of a meter) in diameter.

They slowly cranked up the pressure on the spheres. When the pressure exceeded 40 gigapascals, 400,000 times atmospheric pressure, the arrangement of the bonds between the carbon atoms in the glassy spheres had completely shifted to a form that endowed the spheres with diamond-like strength.

The researchers detected the shift in internal bonding by probing the spheres with X-rays.

They also did experiments in which a glassy sphere was simultaneously subjected to different pressures from different directions, to further assess the strength of the new form of carbon.

While the diamonds in the anvil pressed in on the sides of the sphere with a pressure of 60 gigapascals, about 600,000 times atmospheric pressure, the pressure on the tip of the sphere reached 130 gigapascals.

To read more go to the Stanford Univeristy News Site

See 10 Legendary Diamonds and their stories here

Exotic Quantum Crystal Discovered -

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Nature knows two opposite types of solids: one that emerges upon compression from a liquid and a second that appears if the pressure on a liquid is reduced.

While the former is typical for substances in our everyday life the latter occurs for example in a dense quantum liquid of electrons (such as in metals) or ions (in exotic white dwarf or neutron stars).

Now it has been shown that there exists yet a third form of matter that inherits both of these properties. This unusual behaviour has been predicted to exist in crystals of excitons - hydrogen atom-like bound states of electrons and holes - in a semiconductor quantum well placed in a strong electric field.

A team from Kiel University (Germany) consisting of Dr. Jens Bonning, Privatdozent Alexei Filinov and Prof. Michael Bonitz has performed extensive accurate computer simulations that shed light on the mysterious properties of this material.

The results appear in the current issue of Physical Review B. There the authors present a simple explanation for the coexistence of the two seemingly contradicting melting behaviours.

The secret lies in the character of the forces acting between two excitons: at low pressure excitons repel each other via a dipole force and form a quantum liquid.

Upon compression this fluid freezes into an exciton crystal. Further compression brings two excitons so close together that the quantum wave nature of their constituents (electrons and holes) starts to weaken the forces.
As a consequence, further compression leads to an increasing overlap of the exciton quantum waves that is no longer balanced by the inter-exciton repulsion, and the crystal melts again.

The researchers have made precise predictions where to search for this exotic crystal of excitons (particularly well suited are zinc selenide or gallium arsenide quantum wells) - it is now up to the experimentalists to find this new state of matter.

Crystal mountains speak of moon's molten past - New Scientist

Crystal mountains speak of moon's molten past - space - New Scientist

SUPERMAN'S sparkling Fortress of Solitude they're not, but giant outcrops of crystals, found on the moon by India's Chandrayaan-1 probe, prove that a roiling ocean of magma once engulfed the rocky body of our satellite.

The moon is thought to have coalesced more than 4 billion years ago from the molten debris of an impact between the Earth and a Mars-sized object. Models suggest that heat from that impact, as well as from material compressing to form the moon, created a sea of magma that lasted for a few hundred million years. Heavy, iron-bearing minerals should have sunk through this magma to form the moon's mantle, while lighter, iron-poor minerals called plagioclases should have crystallised and floated to the surface.

But it has been difficult to find direct evidence of the moon's primordial crystalline crust, as it was likely jumbled by meteoroid impacts and paved over by lava flows early in the moon's history. Until recently, the only evidence came from lunar samples collected at a few sites by the Apollo astronauts.

Last year, however, Japan's Kaguya probe spotted patches of the stuff inside a number of craters (Nature, DOI: 10.1038/nature08317). Now, it seems Chandrayaan-1, which orbited the moon for almost 10 months until it failed in August, found the mother lode - vast outcrops of plagioclase crystal along a mountain range inside the moon's 930-kilometre-wide Orientale basin (below). Lava has resurfaced less of Orientale than other craters of its size.

Chameleon Opal: Takes on any Colour

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A new material could give a chameleon a run for its money - it can rapidly change colour to match that of any in the visible spectrum.

The synthetic material can be likened to an opal, a mineral that owes its variety of colours to its layered structure: regions with a high refractive index, in which light travels slowly, are interleaved with regions with a low refractive index. Light waves with a wavelength - or colour - similar to that of the space between layers are scattered in a way that gives opal its iridescent sheen.

The chameleon-like "opal" developed by British and Canadian chemists has a similar layered structure. But their material goes one better than nature. It can rapidly shrink or swell to change the distance between its layered regions, changing the colour of light that it scatters (see video above).