A very rich specimen of Ardennite-(As), a rare silicate arsenate of manganese and aluminum, which has the type locality in this Belgian town. Formed by some  aggregates in parallel growth of prismatic flattened crystals, intense color between orange to yellow and luster. They are included in a quartz matrix with hematite. Collect samples is currently prohibited and specimens are very difficult to find (I know it). From the collection of P. Van Hee.