Round faceted blue kyanite (aluminum silicate) gemstone, 6 mm in diameter. Indigo blue with strong variations in hue due to natural pleochroism. Material acquired at a wholesale lapidary market, Brazil.
Piece Details
| Mineral |
Blue Kyanite (aluminum silicate, Al₂SiO₅) |
| Dimensions |
6 mm in diameter. Variation of ±0.1 mm. |
| Shape and Back |
Round faceted (brilliant cut) |
| Finish |
Faceted with vitreous luster |
| Hardness |
4.5 Mohs (parallel to crystal) / 7 Mohs (perpendicular) — characteristic anisotropy; we recommend a closed bezel setting to protect the edges |
| Origin |
Brazil |
| Treatment |
Untreated |
| Piece Type |
Unique piece |
This specific piece
The indigo blue of this kyanite is rich and deep, with the tonal variations characteristic of pleochroism: observed from the long axis of the original crystal, the gem may appear lighter and almost sky blue; from the perpendicular axis, darker and more intense.
The round brilliant cut maximizes light return through the upper facets (crown) and the lower pavilion, highlighting the mineral's characteristic tonal variation.
How kyanite's pleochroism is formed
Kyanite is an anisotropic mineral: its triclinic crystal structure causes light to propagate at different speeds depending on the direction.
What setting it works for
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Bezel setting (925 silver) — recommended due to hardness anisotropy: it protects edges parallel to cleavage, which are the most fragile to lateral pressure. The bezel distributes force peripherally.
-
Pendant with simple claw setting (3 or 4 claws) — viable if the claws do not fall on the soft cleavage plane; requires precision in positioning.
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Wire wrap — delicate alternative; handle the gem carefully during wrapping to avoid pressing on the soft plane of the kyanite.
Kyanite in lapidary tradition
Kyanite owes its name to the Greek kýanos (blue), the same root as "cyan" and "cyanide". It is a polymorphic mineral of andalusite and sillimanite — all three are aluminum silicates with the same chemical formula but different crystal structures
In the lapidary markets of Brazil, Nepal, and Tanzania, blue kyanite is worked mainly for collectors and alternative jewelry.
In crystal tradition, blue kyanite is associated with mental clarity and direct communication. The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice or a substitute for professional care.
How to recognize genuine kyanite
The most characteristic sign is differential hardness: on the long axis of rough crystals, hardness is 4.5 Mohs; on the perpendicular, 7 Mohs. In a faceted gem, this means that some edges are more susceptible to chipping upon impact than others.
Frequently Asked Questions
Is kyanite suitable for a ring?
Due to its anisotropic hardness and cleavage, kyanite is more suitable for earrings and pendants. For rings, we recommend occasional use and a closed bezel setting to protect the perimeter from direct impacts.
Does pleochroism fade over time?
No. Pleochroism is a structural optical property of the mineral, not a treatment. The change in hue depending on the angle is permanent and intrinsic to kyanite.
Does it have any treatment?
Untreated. Blue kyanite does not require any process to achieve its color — the blue is entirely natural due to the presence of iron and chromium in the crystal lattice.
Why does the blue vary so much between pieces?
The color depends on the specific metamorphism conditions and the mineral inclusions present in each crystal. No two kyanites are exactly alike in hue.
What are the exact dimensions?
6 mm in diameter with a variation of ±0.1 mm. Verify with a caliper before choosing a setting.
How is it cared for?
Clean with a soft, dry cloth. Avoid ultrasonic and steam cleaners — micro-fissures from cleavage can propagate. Store padded, separate from harder minerals. More at jewelry care.
See also: cabochons collection · faceted gemstones · silversmithing.
