[mass noun] A rare mineral occurring as emerald green or blue-green crystals. It consists of a hydrated silicate of copper.
- ‘A number of lots of very fine dioptase had recently come to America from this locality.’
- ‘We had traveled across twelve time zones and back in time at least fifty years to get dioptase at the source, but our timing was as poor as the specimens.’
- ‘The Algomah mine is best known for lapidary material and copper-bearing microminerals, including (but not limited to) plancheite, kinoite, dioptase, azurite, and atacamite.’
- ‘For digital photography, SoLux bulbs are perfect, yielding accurate rendition of difficult-to-photograph minerals such as dioptase and azurite.’
- ‘Tantara dioptase occurs well crystallized with quartz, plancheite, shattuckite, fornacite, and chrysocolla.’
- ‘Additional details of its history and mineralogy can be found in a Rocks & Minerals article published in concurrence with the 1985 Tucson Show, at which dioptase was the featured mineral.’
- ‘Many of the best Tsumeb cerussite, dioptase, azurite, smithsonite, and other specimens passed through his hands en route to some faraway collection.’
- ‘The color of dioptase does not photograph well and must be seen in person to appreciate.’
- ‘Other Bisbee occurrences include the Shattuck shaft where it occurred in fibrous crystals to 5 cm associated with dioptase and the Southwest mine where thick crusts of parallel acicular crystals to 90 cm across were found.’
- ‘The mine is well known for the rare secondary copper minerals that occur in the lode, including paramelaconite, cuprite, malachite, and dioptase.’
- ‘Dioptase is a very beautiful mineral and it is one of the few minerals that can challenge the peerlessness of emerald's deep green.’
- ‘A good example of this potential for confusion is illustrated in specimen CM7075, dioptase, most probably from the type locality for the species in Altyn-Tube, Qaraghandy Oblys, Kazakhstan.’
Early 19th century: from French, formed irregularly from Greek dioptos transparent.
We take a look at several popular, though confusing, punctuation marks.