Cerussite - Jackstraw Spear on Iron-Stained Blades, Congo

A single elongated Cerussite spear rising clean out of a jackstraw cluster, from the celebrated oxidised lead workings at M'fouati in the Republic of the Congo. The locality is the modern benchmark for this habit, and what separates an exceptional piece from routine production is precisely what is on show here: one dominant crystal of real length and transparency, held aloft and unobstructed, rather than a tangle in which no individual asserts itself. The architecture is the point. From a compact basal cluster of interpenetrating blades, lying at every conceivable angle in the chaotic jackstraw manner that gives the material its name, a single sharply tapering crystal climbs free for the majority of the specimen's height. It leans very slightly off vertical, which reads far better than rigid symmetry would, and the supporting blades radiate outward beneath it in a rough rosette. The result is a piece with genuine three-dimensionality despite a slender footprint of only 1.7 cm in depth; viewed from the sides and from the front it presents three quite different silhouettes. In ordinary reflected light the main crystal is a pale smoky grey-brown, almost colourless along its length, warming to a faint tawny amber where the striated prism faces stack together. Where light passes through the thinner tapering tip the crystal goes essentially water-clear, and the whole blade behaves as a light pipe, carrying illumination down into the cluster. The lower blades are darker, flushed with the deep brick and oxblood tones of the iron oxide that coats and invades them, so the specimen moves from earthy red at the base to glassy transparency at the summit. Lustre is the high adamantine-to-vitreous brilliance that Cerussite owes to its very high refractive index. Turned slowly under a directed beam, the longitudinal striations on the prism flash in sequence, and the sub-parallel blades beneath set off a staggered glitter as each catches the light in turn. The terminal region of the leading crystal gathers light into a bright point. The iron-oxide encrusted blades serve as their own matrix, their matte red roughness throwing the glassy spear into sharp relief; there is no extraneous host rock to distract. The piece is mounted upright on a clear acrylic base. At 7.1 x 3.0 x 1.7 cm this is a small cabinet specimen with a presence well beyond its mass. Long, slender Cerussite blades are brittle and heavily cleaved, and a projecting needle of this proportion is among the most vulnerable things in the mineral kingdom; such crystals are routinely lost at the point of extraction, which is why intact spears of this reach remain difficult to source. Under a single directed light it reads as a shard of glass rising from embers.