from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A mixture of clay minerals and iron oxides formed by alteration of olivine

from The Century Dictionary and Cyclopedia

  • n. A silicate of iron, calcium, and magnesium found in the augite-andesite of Carmelo Bay, California. It is probably an alteration-product of olivin.


Sorry, no etymologies found.


  • This heating occurred only when the meteorite fell toward Earth, so the iddingsite and whatever it enclosed had to be there prior to the journey.

    First Contact

  • What he says is the inevitable conclusion: The microbes died and became encased within the iddingsite while on Mars.

    First Contact

  • Nobody has a foolproof chemical method for telling what microfossils are terrestrial and which are extraterrestrial, so McKay has offered two other defenses of his conclusion: The microfossils in two additional Mars meteorites now being studied are encased in the mineral iddingsite in a way that could have occurred on Mars but not later on Earth.

    First Contact

  • Even more significant, the iddingsite near the outer zone of the meteorite had been altered by the crust that formed there as the red-hot meteorite sped into the earth’s atmosphere.

    First Contact


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