Tumbled dumortierite in quartz from Brazil: milky quartz with acicular blue dumortierite inclusions that form veins and patches on the white matrix. Available in two sizes—small 18×14 mm and large 30×15 mm—with a unique pattern on each piece. Commercially known as "blue quartz."
Material Data Sheet
| Mineral |
Macrocrystalline quartz with dumortierite inclusions (blue aluminum borosilicate) |
| Color |
White to translucent base with intense blue to grayish-blue veins and patches |
| Size |
Small format 18×14 mm; large format 30×15 mm (natural variations) |
| Shape |
Tumbled; smoothly rounded surface |
| Finish |
Smooth polished finish characteristic of tumbled stones |
| Hardness |
7 Mohs (matrix quartz) — suitable for daily wear, wire-wrapped jewelry, and pocket stone |
| Origin |
Brazil — dumortierite-bearing quartz deposits in Minas Gerais and Bahia |
| Treatment |
Untreated. The blue color comes from native dumortierite inclusions in the quartz matrix |
| Type of piece |
Each tumbled stone has a unique vein pattern; shipping by intuitive selection within the chosen format |
How this pattern is formed
Dumortierite is an aluminum borosilicate that crystallizes in fibrous aggregates of intense blue. When incorporated during quartz formation, the fibers become trapped within the crystalline matrix and produce the characteristic veined appearance of "blue quartz." Unlike lapis lazuli (a mineral aggregate) or sodalite (a homogeneous mineral), here the blue appears distributed in patches and veins on a translucent white background, revealing the internal structure of the quartz.
What this format is good for
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Wire wrap — 7 Mohs hardness withstands medium and fine gauges without marks; large formats (30×15 mm) have enough presence for a main pendant, small ones (18×14 mm) work well for earrings or bracelets
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Macramé — light to medium weight and smooth surface facilitate direct knotting; the blue/white contrast adds visual focus to natural thread compositions
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Pocket stone — compact format and high hardness, no risk of chipping; traditionally associated with mental clarity and sustained focus
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Collecting — the variability of the pattern makes each tumbled stone unique; interesting for mineral collections with blue inclusions
Dumortierite in cultural tradition
Dumortierite was first described in 1881 by the French mineralogist Eugène Dumortier, after whom it is named.
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 dumortierite in quartz
Authentic dumortierite quartz shows irregular blue veins, with blurred edges where the mineral fibers penetrate the surrounding quartz. Under 10× magnification, the fibrous, non-homogeneous structure of the inclusions is visible. Imitations of dyed quartz tend to have a uniform blue that penetrates through internal fractures and leaves dark edges where the pigment accumulates.
Frequently Asked Questions
What is the difference between "blue quartz" and pure dumortierite?
"Blue quartz" is macrocrystalline quartz with dumortierite inclusions; pure dumortierite is a compact, homogeneous blue mineral without a visible matrix. This selection is the version with quartz: the blue appears in veins and patches on a translucent white background, not as a uniform block.
Do the two formats come from the same material?
Yes. Small (18×14 mm) and large (30×15 mm) are cut from the same Brazilian material; the size of the final tumbled stone changes, but the composition and range of blue tones are the same.
Is it suitable for daily wear rings?
In tumbled format, it works best in wire-wrapped pendants, bracelets, and earrings, where the rounded surface is part of the visual appeal. For rings, we prefer cabochons with a flat back; see the cabochon collection for formats suitable for bezel setting.
More about dumortierite: properties, meaning, and uses. See also: all tumbled stones · meditation stones.
