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The Value of Infrared Telescopes
“Infrared telescopes such as Spitzer and now Herschel are providing an exciting picture of how all the ingredients of the cosmic stew that makes planetary systems are blended together,” said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. The Spitzer observations were made before it used up its liquid coolant in…
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Jets Transport Crystals Through Solar Systems
Poteet and his colleagues say this scenario could still be true but speculate that jets might have lifted crystals into the collapsing cloud of gas surrounding our early sun before raining onto the outer regions of our forming solar system. Eventually, the crystals would have been frozen into comets. The Herschel Space Observatory, a European…
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Forsterite Crystals
The crystals are in the form of forsterite. They belong to the olivine family of silicate minerals and can be found everywhere from a peridot gemstone to the green sand beaches of Hawaii to remote galaxies. NASA’s Stardust and Deep Impact missions both detected the crystals in their close-up studies of comets. “If you could somehow transport yourself inside…
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Temperatures as Hot as Lava
“You need temperatures as hot as lava to make these crystals,” said Tom Megeath of the University of Toledo in Ohio. He is the principal investigator of the research and the second author of a new study appearing in Astrophysical Journal Letters. “We propose that the crystals were cooked up near the surface of the…
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Descending Olivine Crystals
Tiny crystals of a green mineral called olivine are falling down like rain on a burgeoning star, according to observations from NASA’s Spitzer Space Telescope. This is the first time such crystals have been observed in the dusty clouds of gas that collapse around forming stars. Astronomers are still debating how the crystals got there, but the most likely…
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Imitation Tourmaline
Imitation tourmaline is occasionally seen. The popular watermelon tourmaline and other parti-colored tourmalines are a common target of the imitators. Some assembled imitation stones consist of a thin wafer of colored glass or plastic, glued between two pieces of colorless glass. These imitations are easy to detect with a microscope or loupe. If the stones…
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Tourmaline Treatments
Heat and irradiation are common treatments used to improve the color of tourmaline. Both of these treatments are commonly done after the stones have been cut and polished. They can be undetectable when viewed with a gemological microscope. Heat treatment can lighten an undesirable tone in some materials and give some brownish stones a brighter,…
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Pleochroism in Tourmaline
Tourmaline is a pleochroic mineral. That means its apparent color can change with different directions of observation. The color is usually darkest looking down the c-axis of the crystal (down the long axis). It is usually lightest when viewing perpendicular to the long axis of the crystal. Cutting pleochroic gem materials requires skill and knowledge.…
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Cat’s-Eye Tourmaline
Tourmaline is one of many minerals that can be chatoyant when cut into a gem. “Chatoyant” is a gemological adjective used to describe minerals that exhibit a “cat’s-eye”. Chatoyant tourmalines contain thousands of tiny parallel tubes that have the ability to reflect light. When a tourmaline crystal filled with these tubes is properly cut as…
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Color Zoning in Tourmaline
Changing conditions during tourmaline crystal growth often result in single crystals that contain two or more different colors of tourmaline. The earlier color is usually overgrown by the later color. These bicolor crystals are known as “zoned crystals.” Cut gemstones with distinctly different color zones are known as parti-color gems. In many gems, color zoning…