Apophyllites on matrix, Fengjiashan Mine (Daye Copper mine), Edong Mining District, Daye Co., Huangshi Prefecture, Hubei Province, China. ? Rob Lavinsky, www.iRocks.com. Used with permission.
The gemstones known as apophyllites belong to a solid solution series of minerals that includes fluorapophyllite-(K), fluorapophyllite-(Na), and hydroxyapophyllite-(K). Fluorapophyllite-(K) is the most commonly found type.?The rarest,?fluorapophyllite-(Na), crystallizes in the orthorhombic system, while the others form in the tetragonal system.
Apophyllite’s extremely perfect and easy cleavage makes it very fragile and dictates that gem cutters choose an orientation with the table of a faceted stone not perpendicular to the crystal’s long axis.
Fluorapophyllite rough and cut set. Crystal specimen: 7.0 x 4.2 x 2.3 cm; Portuguese-cut gem, 8.58 cts. Jalgaon, Maharashtra, India. ? Rob Lavinsky, www.iRocks.com. Used with permission.
Apophyllite’s optic sign may vary. It?may be uniaxial positive or negative.
Material from Poona, India shows the following properties:
No known synthetics.
Apophyllites may receive diamond-like carbon (DLC) and synthetic diamond film coatings. These treatments may improve the gems’ wearability and resistance to scratching.
Radiation can turn colorless material green, but?heating may reverse this process.
Mumbai (Bombay), Maharashtra, India produces colorless as well as intense, apple-green colored crystals, due to the presence of iron.?These iron-rich apophyllites occur in magnificent crystal groups. However, facetable material is usually rare and smaller than the colorless variety. Many other sites in Maharashtra produce apophyllites.
Other notable sources include the following locations:
- United States: Colorado; Michigan; New Jersey; Oregon; Pennsylvania; Virginia; Washington.
- Bay of Fundy, Nova Scotia, Canada.
- Guanajuato, Chihuahua and San Martin, Zacatecas, Mexico.
- Australia; Brazil; Bulgaria; Canada; China; Faroe Islands; Finland; Germany; Iceland; Ireland; Italy; Japan; Russia; Scotland; South Africa; Sweden.
Gem cutters seldom facet apophyllites. Furthermore, facetable rough greater than 10 carats in size is very rare. Stones faceted as curiosities are usually colorless. However, custom gem cutters have faceted the green Indian material.
- Smithsonian Institution (Washington, DC): 15.4 (colorless, step cut).
- Devonian Group (Calgary, Alberta, Canada): 7.05 (colorless, Poona, India).
- Private collection: 24.92 (freeform, Poona, India).
You’re more likely to find apophyllites in mineral collections than in jewelry collections. In addition to perfect cleavage and relatively low hardness (4.5 to 5), this gem has great heat sensitivity. The heat from a jeweler’s torch may cause these gems to exfoliate. In other words, true to its etymology, apophyllite may lose flakes or “leaves” of material if heated.
Any apophyllites used in jewelry should have protective settings. Limit them to occasional wear.
For cleaning, use a soft brush, mild detergent, and warm water. Consult our gemstone jewelry care guide for more recommendations.
Apophyllite: India (1.3, 8.6, 2.4). Photo ? Joel E. Arem, PhD, FGA. Used with permission.