• Chemical Formula: Sb2O3, Antimony Oxide.
  • Class: Oxides and Hydroxides
  • Uses: A minor ore of antimony and as mineral specimens.
  • Specimens

Senarmontite is, in some respects, an under appreciated mineral. It is rather scarce and not very well distributed, so good specimens are hard to find. It forms excellent octahedral crystals that can be transparent with a high luster. Specimens with dozens of octahedrons of randomly varying sizes are especially admirable.

Senarmontite is dimorphous with the mineral valentinite. Both minerals have the exact same chemistry, but they have different structures. Senarmontite is isometric and valentinite is orthorhombic. It is similar to the situation between diamond and graphite. Valentinite is associated with senarmontite as well as stibnite. Actually both senarmontite and valentinite are oxidation products of the antimony sulfide.


  • Color is colorless, white or gray.
  • Luster is vitreous, adamantine, greasy or resinous.
  • Transparency: Crystals are translucent to transparent.
  • Crystal System is isometric.
  • Crystal Habits typically include well formed octahedral crystals but more commonly massive as well as granular and encrusting.
  • Cleavage is imperfect.
  • Fracture is conchoidal.
  • Hardness is 2 - 2.5
  • Specific Gravity is approximately 5.3 - 5.5 (heavier than average).
  • Streak is white.
  • Associated Minerals include quartz, stibnite , valentinite, kermesite, native antimony, stibiconite and other antimony minerals.
  • Notable Occurrences are limited to the Djebel-Haminate Mine, Ain Beida, Qacentina (Constantine), Algeria and Ham Sud Township, Wolfe County, Quebec, Canada.
  • Best Field Indicators are crystal habit, high luster, associations and specific gravity.
(hover for more info)
SENARMONTITE specimen sen-1
$ 25.00
Dims: 0.2 x 0.2 x 0.2" (0.5 x 0.5 x 0.5 cm)
Wt: 0.4 g
Djebel Delar, Algeria
This tiny specimen consists of a single Senarmontite octahedron. It is in fair to poor condition, as a substantial portion of it has been cleaved off. However, where it is intact it still has a good octahedral form, with relatively well-defined edges and clean faces that possess a dull pearly luster. It has a pale gray coloration and is translucent to dimly transparent, though a thin coating of impurity might be interfering with clarity. There is no host rock present, obviously.
no photo
sen-1 ($ 25.00)
Djebel Delar, Algeria
SENARMONTITE specimen sen-2
$ 30.00
Dims: 0.2 x 0.1 x 0.1" (0.5 x 0.5 x 0.4 cm)
Wt: 0.3 g
Djebel Delar, Algeria
A single octahedral Senarmontite crystal makes up this tiny specimen. It is in excellent condition, showing only a very small amount of damage, and has excellent octahedral form, with well-defined edges and very clean faces that possess a dull pearly luster. It is generally colorless and transparent, though tiny dark inclusions give it a gray coloration and interfere with clarity. Of course there is no host rock present.
no photo
sen-2 ($ 30.00)
Djebel Delar, Algeria
SENARMONTITE specimen sen-3
$ 25.00
Dims: 0.2 x 0.2 x 0.2" (5 x 5 x 5 mm)
Wt: 0.3 g
Djebel Delar, Algeria
A single, tiny Senarmontite crystal comprises this specimen. It is in fair condition, showing considerable damage, but none of this damage appears to be fresh. Its octahedral form, however, is excellent- where intact, it possesses well-defined edges and clean faces. Its color is a dull, pale gray, and its luster is waxy or greasy at best. It is nearly transparent, however. As with our other Senarmontite specimens from this locality, there is no host rock present.
no photo
sen-3 ($ 25.00)
Djebel Delar, Algeria


Copyright ©1995-2023 by Amethyst Galleries, Inc.