Fine narsarsukite crystals from Mont Saint-Hilaire are the world’s best. They occur in more than one geological environment at the locality, and the crystals embedded in the igneous breccia like this one can be spectacular for the species. This crystal is a good size, at 1.2 cm, in a matrix 3.5 cm tall. At Mont Saint-Hilaire, many of thenarsarsukite crystals embedded in the breccia reacted with as they grew in the breccia, and so it is common to see crystals that are either not fully developed, or that show inclustions/intrusions of the breccia. This crystal illustrates the latter a little bit at bottom centre. This crystal exhibits stongly contrasting colour zoning – the dark green is cause by microscopic inclusions of amphibole. One unusual feature of this one is a paler translucent zone right at the edges of the top corner of the crystal. Another notable characterisitc is that while some of narsarsukites are only very thin plates, this one has a nice three-dimensional corner that is well exposed. In excellent condition, one small chip on the left edge, not easy to distinguish from the breccia interaction without magnification. Hard to obtain in a size like this, these days, this is a very good, sharp, lustrous narsarsukite crystal.