Allemonite refers to the locality Allemont where it is found in veins at Allemont, Isère, France. It ranges in colour from white, grey, greyish white and can be reddish white on fresh surfaces.

It occurs in Reniform ("kidney like") structure. Any mixture of arsenic and antimony that has 80% or more of one element is classified as that element.

Eg. a specimen with a ratio of 80% arsenic ;and 20% antimony is recognised as Arsenic. Conversely, a specimen with 80% antimony and 20% arsenic is recognised as Antimony.

Any combination with less than 80% of either arsenic or antimony is classified as Stibarsen.

STIBARSEN FIELD INFORMATION

Prospectors for minerals frequently use metal detectors as an adjunct to traditional mineral exploration methods such as field reconnaissance, rock chip and soil sampling.

Whilst exploring a parcel of country in the Palmer River area, carrying metal detectors at the time while navigating a small, well incised gully one of the team obtained a metal detector signal.

What appeared to be a small thumb-sized rock was the culprit. Breaking this rock open revealed a silvery metallic interior.

At first it was thought to be some sort of slag from historical explorers casting metal. However, more intense scrutiny of the area resulted in many more nodules being found. Returning home an XRF analysis of a sample revealed the material to be Native Antimony.

Attempts were made to locate the source of the nodules and it was suspected that they formed at the nearby interface between a mylonitic Granite and Amphibolite of Meso Proterozoic age that subsequently underwent siluro-devonian deformation and metamorphism.

Subsequent exploration of the surrounding area uncovered sporadic nodules over a wide area. Historical diggings were located about 700 Metres distance from the original find.

At his location a 5 kg piece of unknown metallic mineral was located which after tests by the National Museum of Victoria, the material was identified as Stibarsen.

After extensive exploration the source was eventually located. The Stibarsen is hosted in a vein breccia with the “outcrop” flush with the ground surface. The exact locality is a secret.