What is a zeolitic mineral, grayish white or yellowish, occuring in delicate groups of crystals, also fibrous massive. It is a hydrous silicate of alumina, lime, and soda called?

mesolite — A zeolitic mineral, grayish white or yellowish, occuring in delicate groups of crystals, also fibrous massive. It is a hydrous silicate of alumina, lime, and soda. (Webster's 1913.)

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