Although not well known, scapolite would make an attractive gem material for both jewelry enthusiasts and mineral collectors. It comes in a wide variety of colors and can show dramatic fluorescence. Rare specimens also display phenomenal effects, like chatoyancy.
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Myanmar: yellow to orange in LW (U spectrum), also pink in SW. Tanzania: strong yellow in both LW, SW; violet stones = pink in SW, inert in LW. Quebec: massive material fluoresces in LW (+ phosphorescence). Some yellow faceted gems fluoresce lilac in SW. Strong orange in X-rays.
Scapolite comes from the Greek skapos for “shaft,” because of the stumpy nature of its prismatic crystals. Marialite was named after Maria Rosa, wife of German mineralogist G. vom Rath. Meionite comes from the Greek meion for “less,” because its pyramidal form is smaller than that of idocrase from Vesuvius, which it resembles. Mizzonite comes from the Greek meizon for “greater,” because the axial ratio is larger than that of meionite. Wernerite was named after the mineralogist Abraham Gottlob Werner.
In contact zones; regionally metamorphosed rocks; altered basic igneous rocks.
The scapolite mineral group contains a solid state series from marialite to meionite, with mizzonite as the intermediate member. Gemologically speaking, the term scapolite refers to the gems that form in this series. Older sources may refer to this series as “wernerite.”
The colors and properties of scapolites vary as the amount of sodium and calcium in their chemical composition changes. Colors range from near colorless through pinks and purples to yellow and orange. By far, yellows occur most commonly. Purples come a distant second. Scapolites may show strong fluorescence and pleochroic colors.
Graph of Scapolite Optical Properties Versus Chemical Composition
Refractive index (RI) and birefringence (δ) as related to chemical composition in the scapolite series. Chemistry expressed as (molecular) percent meionite, which reflects the ratio Ca/(Ca + Na) in the formula. Refractive index plotted as a mean index = (o + e)/2. Adapted from W. A. Deer, R. A. Howie, and J. Zussman, 1962, The Rock Forming Minerals, vol. 4 (New York: Wiley), p. 329.
Heating can improve color. This common enhancement is undetectable.
Yellow and colorless scapolites may receive radiation treatments. This uncommon enhancement creates a brownish purple color, which fades rapidly.
Tanzania produces the finest golden yellow scapolite known in commercial quantities. Dodoma yields transparent, golden yellow to orangey yellow gem material. This source sometimes produces very pale to near colorless stones, as well as violetish and pink (rare) cuttable crystals.
Espirito Santo, Brazil produces pale yellow crystals, sometimes large and facetable.
The pink and purple Tanzanian material is extremely rare in sizes over 5 carats. You’ll find most gems of this color in the 1-2 carat range.
Brazilian yellow scapolite is cuttable up to about 30 carats. However, at that size, it’s usually flawed (long thin tubes).
Faceted Myanmar scapolites are rarely encountered on the market. However, white and yellow specimens from Myanmar have been found in large sizes. Pink Myanmar step-cut gems to 70 carats have been reported. Cat’s eyes usually run under 10 carats. However, larger ones are known.
Royal Ontario Museum (Toronto, Ontario, Canada): 28.4, 57.6 (yellow, Brazil); 7.91 (pink, Myanmar); 65.63 (colorless, Myanmar); 18.8 (gray, cat’s eye); and 18.3 (pink cat’s eye).
With a hardness of 5.5 to 6 and perfect cleavage, scapolites require care when setting and wearing as jewelry. Although daily wear as a ring stone may be inadvisable, protective settings and occasional use will let you show off these rarely seen gems. Scapolites would make excellent choices for pendants and earrings.