This is a particularly fine example of two generations of crystal growth. The first generation calcite crystals are sharp scalenohedra with good lustre – they have hematite phantoms inside and some thin hematite coatings in a few places. The next generation are translucent rhombohedra – they formed around and partially enclosing the first generation crystals, giving quite an effect. This is classic material, referred to as the example of two generations of crystal growth in John Sinkankas’ 1964 classic Mineralogy for Amateurs. Under short-wave UV light, the first generation crystals are vibrant orange and the second generation crystals are dark, making for a gorgeous piece – the first generation crystals are like bright glowing ember. In very good condition, a few small cleaves. A cool piece!