Nepheline, leucite, idocrase, and meionite have not yet been seen at the peak of.    From Wordnik.com.  [Travels to the Equinoctial Regions of America] Reference

I think we may fairly assert that such minerals as tourmaline, jargoon, peridote, spinel and chrysoberyl, though their names may be familiar, are not stones which would be recognized by any but those who are in some sense experts; while other minerals, such as sphene, andalusite, axinite, idocrase and diopside, are possibly almost unknown to most people, even by reputation.    From Wordnik.com.  [Scientific American Supplement, No. 1082, September 26, 1896] Reference