- Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosi Department, Bolivia
- Miniature, 4.3 x 3.9 x 2.1 cm
Monazite gets its name from the Greek word "monazein," which means "to be alone," in allusion to its isolated crystals and their rarity when first found. This is a remarkable, very well crystallized, ridiculously rare, specimen consisting of sharp, lustrous, crystals of orange-pink, crystals of Monazite-Ce on Quartz matrix. Some of the Monazite-Ce crystals are twinned as well. The crystals on this specimen are very good sized compared to most I've seen from Siglo XX. Monazite is usually found in granitic pegmatites, but these crystals are found in hydrothermal tin veins where is an absolute absence of Thorium (usually a trace element in Monazite). It is very difficult to obtain any specimens of this incredibly beautiful and rare phosphate, especially in crystals from Bolivia like this. This piece is from the same mine for which this material was discovered along the Contacto and San Jose veins in this mine and was first described by Sam Gordon and Mark Bandy. It is so unbelievably rare to find matrix specimens of Monazite-Ce from any locality in Bolivia or anywhere else in the world. This species is often dark and opaque from most localities and rarely bright like these. These crystals also show a distinct color change in various lightings.