4.20 Top Quality Natural Pollucite Rare Gemstone

Not only is gem-quality pollucite very rare, it’s also the only mineral which has cesium (Cs) as an essential constituent. This mineral serves as the principal ore for cesium.

Pollucite belongs to the zeolite mineral group. It forms a solid solution series, as the cesium analogue, with analcime, the sodium analogue.

Discovered in 1846 in Elba, Italy, this mineral was named after Pollux, the twin brother of Castor in Classical mythology. (Helen of Troy and the ill-starred Clytemnestra were his sisters). The discoverers associated it with castorite, named after Castor, since both occurred in lithium-rich granite pegmatites at this source. Although castorite was later renamed petalite, the name pollucite remained.

Oddly enough, according to myth, Pollux was immortal while Castor was mortal. So, too, did the name “castorite” pass away. Furthermore, some myths claim the twins had different fathers, immortal Zeus and the mortal Tyndareus. So, though originally paired, these minerals proved to be distinct, too.

Pollucites can reach the hardness of quartz and require no special care or settings. You’re more likely to find this gem in mineral collections than in jewelry collections. However, recent gem-quality finds in Afghanistan could change that. See the faceted gem below. Consult our Gemstone Jewelry Cleaning Guide for general care recommendations.


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