the GNU version of the Collaborative International Dictionary of English
n. A loose hydrated form of silica, a variety of opal, deposited in concretionary cauliflowerlike masses, around some hot springs and geysers.
The Century Dictionary and Cyclopedia
n. The variety of opaline silica deposited about the orifices of geysers. It occurs white or grayish, porous, in stalactitic, filamentous, or cauliflower-like forms.
Word Usage
"It is located in the Upper Geyser Basin, and is situated on a mound of geyserite built by its own water."