opal

As nouns the difference between opal and geyserite

is that opal is a mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO₂·nH₂O while geyserite is a type of stone, a mixture of quartz and opal deposited by a geyser as it precipitates out of the boiling water.

As a proper noun Opal

is {{given name|female|from=English}} from the precious stone, invented in the nineteenth century.