Beauty is the main property of transparent apophyllite. The
second property of the mineral is fragility. The third is its rarity. The outstanding beauty of the growths of apophyllite crystals are highly
appreciated by collectors. Roads and large jewelry apophyllites.
Apophyllite,
aka “Fisheye”
The Swede Karl Rinman, having discovered a beautiful and not
yet described stone on Gotland, took up his independent research. Burning the
find in the flame of the spirit lamp, Rinman discovered an important property:
heated crystals disintegrated along cleavage planes, forming plates of various
thicknesses.
Thirty years later, in 1806, the French scientist Rene Gayouy
will beat this property in the name of the mineral. The ease of crystal
splitting after heating turns into the Greek “apophyllite”, where “apo” means
“after”, “phyllite” is leaf-like.
By that time, however, the mineral was already known to
European miners and prospectors. For the pearl shine on the cleavage planes,
the stone was called the fisheye. A distinct, although much muffled green in
the color of transparent crystals became the basis for the name of the gem
xylochlor (translated from Greek means "wood green").
Apophyllite
Properties
Apophyllite is a complex silicate that combines potassium,
sodium, calcium, along with fluorine and water. The physical and especially
optical properties of apophyllite depend on the balance of elements in the
compound. Modern science distinguishes between three types of mineral.
Fluorapophyllite is characterized by a high concentration of
fluorine, which replaces a hydroxyl group in the crystal lattice of the
mineral. Apophyllite fluoride fluoresces in ultraviolet rays, giving a
yellow-green glow. Due to this feature, fluorapophyllite is also called
fluorapophyllite.
The low fluorine content in potassium apophyllite makes it
possible to classify the compound as hydroxyapophyllite.
Natroapophyllite (a mineral with high sodium content) is less
common in fluorine and hydroxyapophyllite. It differs in natroapophyllitis and
externally. If potassium varieties of the mineral can be both colorless,
greenish, and bluish, then sodium apophyllite is painted in a yellowish or even
tan.
Like all silicates, apophyllite is prone to “contamination”
with impurity metals. A very decorative effect is observed when manganese and
cobalt are included in the crystalline massif of apophyllite. In the presence
of these metals, crystals acquire a beautiful pink tint.
The hardness of apophyllite does not exceed five units on the
Mohs scale . Fragility is an important physical property of apophyllite for
jewelers. The stone is beautiful in faceted faceting, however, the processing
and setting of the faceted insert into the metal is fraught with the danger of
spontaneous destruction of the gem.
Apophyllite
- An Excellent Collection Mineral
In the east - in Evenkia, Yakutia, Buryatia, the Trans-Baikal
region, large crystals of transparent apophyllite, painted in pale pink tones,
are found.
Excellent splices of apophyllite crystals are mined in India.
Indian apophyllites are mostly colorless or tinted in green, greenish-gray, and
tan. The mass of faceted gems ranges from three to fifteen carats - however,
already ten carat emerald cut apophyllite can be estimated at several hundred
dollars. Tender green apophyllites from India are estimated at $ 250 per carat.
The uncontrolled rise in prices for green-toned apophyllites
is hindered by the ease of communicating colorless stone. A short irradiation
of apophyllite with hard electromagnetic radiation causes the colorless stone
to turn green. Therefore, the jewelry market is distrustful of the sudden
appearance of a large number of high-quality apophyllites of expensive green
color.
The instability of the mineral to a dry and warm environment
also prevents the increase in jewelry demand for stone. Apophyllite easily
loses chemically bound water - which leads to discoloration and destruction of
the gem.
Apophyllite
- Stone of Angels
There is a belief that the Creator addressed the gentle and
subtle beauty of apophyllites to angels. It is as if the purity and meekness of
an angel is embodied in every transparent apophyllite. And each owner of such a
stone is kindly soul, softened by temper and lightened by spirit.
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