lutecite

lutecite

[′lüd·ə‚sīt]
(geology)
A fibrous, chalcedony-like quartz with optical anomalies that have led to its being considered a distinct species.
References in periodicals archive ?
Most spherules are composed of chalcedony; some consist of megaquartz or quartzine and lutecite (Fig.
Apparently only the mineralogy has changed; quartzine and lutecite have replaced the anhydrite.
Quartzine and lutecite spherules from the Alibates are probable replacements of sparsely disseminated evaporite minerals, and the spherules displaying growth rings suggest seasonal(?