Non-Zeolite Minerals
Rock&Gem Magazine|May 2020
Constant Companions of Zeolites
BOB JONES

The gem world easily recognizes the lovely blue-white gem called larimar, a recent addition. The gem is really very pretty and colored by trace copper ions. Larimar also has a couple of surprises connected to it.

One minor surprise is that we are told the gem was discovered by Miguel Mendez and Norm Rilling in 1974 as ocean tumbled pebbles in the Dominican Republic beach surf. It was found in the Dominican Republic mountains in 1916. The initial discovery of what we now call larimar was by Father Miguel Domingo Fuertes Loren.

The good Father applied for a mining permit to collect this lovely blue gem, but the government said no. As a result, the original discovery of larimar was forgotten and remained untouched until the 1974 rediscovery. Found at that time by Rilling, he decided to name the blue gem after his daughter Larissa and the sea, hence larimar.

You may ask why write about a lovely blue gem in an article on non-zeolite minerals? It so happens larimar is really the non-zeolite mineral pectolite, which is very often associated with zeolites. When found in cavities of volcanic rock along with zeolites, pectolite looks nothing like larimar. It develops in long, brittle needle-like crystals in radiating fans several inches long and wide.

I’ve collected pectolite in New Street and Prospect Park Quarries in New Jersey, and at times regretted it. Pectolite’s normal crystal form of hard, needle-thin, very brittle, sharp, acicular crystals have an affinity to break off when they penetrate the skin. Without leather gloves, a collector will carry traces of these penetrating needles as a myriad of slivers. Pectolite is common in the New Jersey deposits in its acicular radiating crystal form but is almost unknown in the very prolific and popular zeolite sources in India and the Northwest.

Larimar gem is not the only non-zeolite to recently appear on the market. Another blue mineral, cavansite, showed up in Oregon at the Owyhee Dam site, Lake Owyhee State Park, Malheur County, and also near Goble, Columbia County in 1967. Again, this new mineral had actually been found earlier but not been recognized as new. It should be noted the initial 1961 unidentified discovery of cavansite was by two rockhounds, but it remained unrecognized until 1967. The Oregon discoveries of fine crystals did not create interest, but when found in quantity in 1989 in India, cavansite suddenly became the darling of the mineral world. Cavansite was found in the Deccan Plateau volcanics in four of the more than forty quarries in the Wagholi quarry complex, in Poona, and again in the Lonavala quarry, Maharashtra. What made the discovery really exciting was the number of specimens mined.

This new mineral cavansite is a rich blue color as compared to the Oregon crystals that were a pale blue color. The Wagholi cavansite was found as radiating spherules to an inch or so across each individually positioned all over specimens of white contrasting stilbite or apophyllite. The cavansite was obviously a late-developing mineral. The discoveries in India produced countless thousands of specimens in a short time just when the mineral market was ready for something new. Specimens first introduced in Tucson in 1989 were immediately all the rage, and every collector wanted a specimen. Dealers had no trouble selling their inventory.

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