from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An orthorhombic mineral form of crystalline calcium carbonate, dimorphous with calcite.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A saline evaporite consisting of anhydrous calcium carbonate with the chemical formula CaCO3; it is dimorphous with calcite.
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral identical in composition with calcite or carbonate of lime, but differing from it in its crystalline form and some of its physical characters.
from The Century Dictionary and Cyclopedia
- n. Calcium carbonate crystallizing in the orthorhombic system.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a mineral form of crystalline calcium carbonate; dimorphic with calcite
Over time, the oyster wraps the grain in successive layers of aragonite, giving birth to a rare pearl.
They wandered through the Big Room, mesmerized by the translucent, calcite soda straws in the Doll's Theater, transfixed by threads of aragonite — sharp as needles — that spun around The Temple of the Sun.
They should probably be ordered according to hardness: diamond, olivine, aragonite, ice.
Also, diamond has no oxygen atoms; ice (H2O) has one oxygen atom; aragonite (CaCO3) has three oxygen atoms; olivine ((Mg, Fe)2SiO4) has four oxygen atoms.
I think aragonite, olivine and ice have hexagonal crystals whereas diamond has octahedral.
Therefore, the best order to arrange those four items are: diamond, ice, aragonite, olivine.
I'd order them in order of appearance: diamond (primordial), olivine (one of the earliest condensates), ice (a late condensate), aragonite (post-planet formation).
A: aragonite several answers, e.g. it's the only one found only on Earth, so far; it's the only one known to be made by biological processes
For example: aragonite, diamond, ice, olivine … found on Earth only, found on Earth and in meteorites only, found/detected in the solar system only, only one detected beyond the solar system.
Changes will be much more pronounced in areas such as the Southern Ocean, which will become undersaturated with respect to aragonite in 2050.