Amblygonite is a lesser-known gemstone with a difficult name but beautiful pastel colors. These gemstones are mostly light yellow, but also come in shades of blue and green.
Is Amblygonite rare? As a mineral, not. But gem-quality Amblygonite is incredibly rare, especially in large sizes.
Join us as we uncover all of the properties, powers, prices, and history of Amblygonite in this comprehensive guide!
What are Amblygonite Gemstones?
Amblygonite is a rare semi-precious gemstone that is usually white to light yellow, sometimes blue to green, and rarely pink to purple.
Astrologically, Amblygonite is a lucky stone for the bull (Taurus).
Amblygonite and spodumene are often confused – both are yellow gemstones that contain lithium and aluminum.
However, spodumene is more common. Additionally, spodumene is a lithium aluminum silicate, while amblygonite is a lithium aluminum sodium hydroxide fluorophosphate.
Amblygonite can also resemble petalite and beryl. Beryl is harder (7.5-8 on the Mohs scale) and petalite is monoclinic.
What is amblygonite used for in industry?
Amblygonite uses
As with spodumene, amblygonite’s lithium content (about 10% of the composition) is its most important industrial property. According to the American Chemical Society, amblygonite is one of the few major lithium ores of economic importance, along with spodumene and lepidolite.
The lithium extracted from amblygonite can be used to make aluminum products, batteries, ceramic glazes, and glass, to name a few examples.
Amblygonite can also be used as a source of phosphorus. Additionally, amblygonite can increase the transparency of glass in products such as tableware and porcelain enamel.
Scientists have created synthetic amblygonite, but not for use in jewelry.
Amblygonite Specifications and Properties
As lithium aluminum phosphate fluoride hydroxide, amblygonite’s chemical formula can be written as (Li,Na)AlPO4(F,OH) or LiAl(PO4)F. Amblygonite stones with low sodium content may be referred to as „hebronite.“
The stone belongs to the amblygonite group, which also includes montebrasite, natromontebrasite, and tavorite (not tsavorite). Amblygonite forms a series with montebrasite. (More on these other stones in the next chapter.)
Amblygonite crystals are usually regular, prismatic, and short or columnar. Most crystals are untreated, and freestanding crystals are rare. They can also be compact or bulky.
Amblygonite often forms twins, especially microscopic polysynthetic twins. Polysynthetic twinning occurs when multiple twin crystals are aligned parallel.
Amblygonite differs from rocks such as feldspar in its density, its cleavage, and its reaction to lithium in the flame test (powdered amblygonite produces a bright red flame).
The following are the properties of amblygonite:
Mohs hardness: 5.5-6
Color: white, gray-white, cream, colorless, beige, light yellow, light green, light blue, blue-green, brown; rarely pink to light purple
Crystal structure: triclinic
Luster: glassy, slightly glassy, resinous, greasy, or nacreous; nacreous on cleavage surfaces
Transparency: clear to translucent (gemstone); transparent to opaque (industrial)
Refractive index: 1.577-1.633; decreases with higher fluorine and sodium content
Density: 2.98-3.11
Cleavage: Perfect to {110}, Good to {110}, Clear to {011}.
Fracture: Irregular/uneven or subconchoidal
Striation: white
Luminescence: Fluorescence sometimes present, often incomplete reaction – green, orange, light brown or yellowish-white in LW-UV & light blue, orange or yellowish-white in SW-UV; light blue phosphorescence possible
Pleochroism: none
Birefringence: 0.019-0.027
Dispersion: 0.014 (weak)
