Elongated teardrop black agate cabochon, 26.5 × 10.8 × 7 mm, with an internal map of polished drusy contrasting with the blue-black base of the mineral. The pattern grows from within and does not compromise structural integrity at any point. Cut and mirror-polished in our lapidary workshop.
Item Specifications
| Mineral |
Black Agate (microcrystalline chalcedony, blue-black variety) |
| Dimensions |
26.5 × 10.8 × 7 mm |
| Shape and Back |
Teardrop, flat polished back |
| Finish |
Mirror polish |
| Hardness |
6.5–7 Mohs — we recommend a closed bezel setting |
| Origin |
Material acquired from a wholesale lapidary market |
| Treatment |
No detectable treatment. Statement based on lapidary observation; no formal gemological certification. |
| Piece Type |
Unique piece |
About This Specific Piece
What at first glance appears to be crazing is actually a network of natural drusy —small formations of quartz microcrystals— that grew within the fissures of the agate. After mirror polishing, they reveal a white and gray map against a blue-black background. The effect is almost cartographic: branching veins that follow no predictable pattern, with areas where white almost covers the dark base and others where only a faint trace emerges.
The lapidary decision was to cut the elongated teardrop shape to preserve as much length of the pattern as possible, respecting the area of highest drusy density in the center of the stone. The narrow profile (10.8 mm width) enhances the vertical reading of the map when mounted as a pendant.
How Drusy Forms in Agate
Agate originates in volcanic cavities where silica precipitates in concentric layers. When these layers surround an internal fissure, the silica can crystallize into quartz microcrystals: the drusy. When the section is cut and polished, the crystals are exposed and create the characteristic white pattern on the dark background of the mineral.
Suitable Settings
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Bezel setting (925 silver or other precious metals) — The teardrop silhouette allows for a bezel that follows the contour without covering the central pattern. With a Mohs hardness of 6.5–7, the stone withstands bezel pressure well; we recommend a closed setting to protect the profile.
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Statement pendant — The elongated profile (26 mm) hangs elegantly from a loose bail or a silver mount with an integrated loop.
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Wire wrap — The flat back facilitates wrapping; a thick wire core can secure the stone without pressing on the front drusy.
Agate in Lapidary Tradition
Agate was carved into seals since predynastic Egypt and into Roman intaglios, where the contrast between mineral layers allowed for the creation of relief portraits. In medieval Europe, black agate was associated with protection and steadfastness (Black Agate, wisdom and steadfastness).
The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice.
How to Recognize Genuine Agate
Natural agate is cool to the touch and takes several seconds to warm up. Under magnification, it shows microcrystalline textures; glass or resin have more homogeneous surfaces. In dark varieties, perfectly uniform black can be a sign of dyeing.
Frequently Asked Questions
How do I know if this black agate is dyed?
We cannot confirm without laboratory analysis. Very dark agates are often treated chalcedony; lapidary observation did not detect obvious signs of dyeing, but we declare it as "No detectable treatment" which is not equivalent to gemological certification.
Can I set this piece in a jewelry bezel?
Yes. With a Mohs hardness of 6.5–7, agate withstands the pressure of a well-executed bezel. We recommend a closed bezel made of 925 silver. The internal drusy are not structural weaknesses —they are natural formations consolidated within the mineral mass.
How do I care for this stone?
Clean with lukewarm water and a soft cloth. Avoid ultrasonic cleaners and steam if mounted. Unmounted, agate is hard enough for everyday use. More information can be found in jewelry care.
Are the dimensions exact?
26.5 × 10.8 × 7 mm. As it is hand-cut, there may be a variation of ±0.5 mm in any dimension.
More about this mineral: properties and uses of agate. See also: loose cabochons · lapidary collection.
