Zektzerite, 0.42 cts. Photo © Joel E. Arem, PhD, FGA. Used with permission.
Small, cuttable crystals of very rare zektzerite are found only in a mountainous location in Washington state. Faceted pieces would make prized specimens for any collection of American gems.
| Data | Value |
|---|---|
| Name | Zektzerite |
| Colors | Colorless to pink, white, light brownish/tan, light yellowish orange/peach, light purplish pink/lavender. Sometimes has color zoning. |
| Crystallography | Orthorhombic crystals generally tabular, pseudo-hexagonal. |
| Refractive Index | 1.582-1.584 |
| Luster | Pearly on crystal faces, vitreous on cleavage and fracture surfaces. |
| Fracture Luster | Vitreous. |
| Hardness | 6 |
| Specific Gravity | 2.79 |
| Birefringence | 0.002 |
| Cleavage | Perfect in 2 directions |
| Dispersion | Very weak. |
| Luminescence | Fluoresces light yellow or blue in SW, inert in LW, no phosphorescence either SW or LW. |
| Luminescence Present | Yes |
| Luminescence Type | Fluorescent, UV-Short |
| Transparency | Transparent to translucent. |
| Formula |
LiNa(Zr,Ti,Hf)Si6O15. |
| Pleochroism |
None. |
| Optics |
α = 1.582; β = 1.584; γ = 1.584. Biaxial (-). |
| Optic Sign | Biaxial - |
| Etymology |
After Jack Zektzer of Seattle, Washington, who initiated the investigation of the newly discovered mineral. |
| Occurrence |
Very rarely in miarolitic cavities in riebeckite granite. |
| Inclusions |
Liquid-filled fingerprints, veils, crystals. |
Zektzerites on albite matrix, 4.7 x 3.1 x 2.3 cm, crystals up to 6 mm, Washington Pass, Okanogan Co., Washington (type locality). © Rob Lavinsky, www.iRocks.com. Used with permission.
With a birefringence of only 0.002, zektzerite is virtually isotropic. 2V = ~ 0°.
Zektzerites may fluoresce light yellow or blue in ultraviolet (UV) shortwave (SW). However, they have no reaction to UV longwave (LW) and show no phosphorescence in either SW or LW UV.
This large, translucent off-white zektzerite crystal fluoresces blue under UV light. 3.1 x 2.0 x 1.9 cm, Washington Pass, Okanogan County, Washington, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.
Scientists have synthesized zektzerite for research into its crystal structure and physical properties. However, there’s no known jewelry use for this synthetic material.
No known gemstone enhancements or treatments.
To date, facetable, gem-quality zektzerites occur only in a small number of miarolitic cavities in riebeckite granite in Okanogan County, Washington.
Crystals also occur in Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan.
Zektzerite rough and cut set, 1.5 x 1.4 x 1.3 cm (peach-tan crystal on matrix), 0.15 cts (gem, square brilliant cut, 3.1 mm), Washington Pass, Okanogan County, Washington. © Rob Lavinsky, www.iRocks.com. Used with permission.
Crystals may occur in sizes up to 35 mm in size. Some have enough transparency to yield small faceted gems, less than 2 carats. Typical crystals range in size from 4-15 mm in size, sometimes perched on riebeckite crystals.
Cuttable material and, thus, cut stones are exceedingly rare.
You’re more likely to find zektzerites in mineral collections, if at all, than in jewelry collections. Any zektzerites in jewelry should have protective settings. Since they have a hardness of 6, they have greater susceptibility to scratches than more common jewelry stones like quartz and topaz. Their perfect cleavage in two directions and brittle tenacity also make them susceptible to damage from impacts. Therefore, clean these gemstones only with a warm damp cloth, mild detergent, and soft brush. For more care recommendations, consult our gemstone jewelry cleaning guide.
0.84-ct zektzerite, medium pink-orange, freeform cut, 7.3 x 4.7 mm, Golden Horn Batholith, Washington. © The Gem Trader. Used with permission.
IGS Newsletter