Pectolites: “Larimar,” Dominican Republic (cabochons, ~ 6 to 30 carats). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Fibrous pectolite has long been a curiosity for gem collectors. Compact material can make wonderful cabochons, and transparent crystals are rare and usually tiny. In 1974, blue pectolite was found in the Dominican Republic. Known by the trade name Larimar, this blue gem has since become a popular jewelry stone.
Although the mineral pectolite occurs in locations across the globe, these fibrous aggregates are seldom cohesive enough to cut. This material is usually too soft and fragile for jewelry wear. However, if pectolite’s fibers inter-grow, it can become jade-like in toughness as well as appearance. When sufficiently compact, pectolite cabochons take an excellent polish.
Gem-quality pectolite comes mainly from Quebec, Canada and the Dominican Republic.
With colors ranging from white to various shades of blue, Dominican pectolite is the loveliest in the world. Traces of copper contribute to this blue coloration. The finest stones are dark blue and translucent. Known by the trade name Larimar, this variety of compact pectolite can take a very high polish. Though locally abundant, Larimar is a rare gem material.
The minerals pectolite and serandite form a series. Pectolite is the calcium end (Ca). Serandite is the manganese end (Mn).
The refractive indices of this series vary with the presence of Ca and Mn.
Fibrous material has chatoyancy that can give pectolite cabochons a cat’s eye effect.
In longwave (LW) ultraviolet light:
- Orange-pink (Bergen Hill, New Jersey).
- Cream white (Lendalfoot, Scotland).
In shortwave (SW) ultraviolet light:
- Greenish yellow (Scotland).
- Yellowish, orange with green areas (Magnet Cove, Arkansas and Lake County, California).
- Faint yellow with phosphorescence (Paterson, New Jersey).
Although no known pectolite synthetics exist, simulants have surfaced. These include ceramics and glass, such as “Victoria Stone” and “Imori Stone.” However, a gemological analysis can easily identify these.
Some Larimar gems may resemble turquoise or dyed howlite, and other compact pectolites may resemble jade. Again, these can usually be distinguished easily.
No known common gem treatments.
In addition to the Dominican Republic, other notable sources include:
- Canada: Thetford Mines and Asbestos, Quebec, produce magnificent, prismatic crystals, the only sources of facetable pectolite. Twinned crystals up to 5” long, colors range from white to pale blue-green.
- Alaska: massive, jade-like stones (used as a jade substitute); also fine-grained, pale blue-green.
- Magnet Cove, Arkansas: pinkish manganiferous material.
- Lake Count, California: dense material suited for cabochons.
- New Jersey; Paterson area, in fine radial sprays: also at Franklin and Sterling Hill.
- Greenland: manganiferous material.
- Czech Republic; Japan; Morocco; Russia; Scotland; Sweden; South Africa.
Lapidaries have cut cabochons up to a few inches from dense, massive, or fibrous material. Small, faceted gems mined in 1973 from Asbestos, Quebec range in size up about 3 carats. Only a few stones have been faceted.
Although some pectolite stones, especially Larimar, are relatively tough, their hardness range (from 4.5 to 6) makes them susceptible to scratches. Popular jewelry stones, such as quartz, topaz, corundum, and diamond, will scratch them. So, store your pectolite jewelry separately from such pieces. Use protective settings for rings. Pectolite cabs make excellent stones for pendants and earrings. Clean your gems and jewelry pieces with a soft brush, mild detergent, and warm water. Consult our gemstone jewelry cleaning guide for more recommendations.