Cordierite - Rough

Locality: Madagascar

Description: This rough cordierite from Madagascar is a natural lapidary material that can show shades of blue-gray, violet-blue, smoky gray, or brownish blue depending on the piece and the lighting. In rough form it is usually sold as chunky, uneven fragments or natural masses with a raw surface and occasional flashes of internal color where the stone breaks cleanly. Some pieces may appear more muted on the outside but reveal stronger color once cut or polished, which is one reason cordierite is popular with lapidary workers and collectors.

Cordierite is a magnesium iron aluminum silicate that forms most often during high-grade metamorphism, when existing rocks are altered by intense heat and pressure deep in the crust. It is well known for strong pleochroism, meaning it can show different colors from different viewing angles, a trait especially noticeable in gem-quality material known as iolite. Madagascar is an important source of many lapidary minerals, including cordierite, and rough from the region is commonly used for cabochons, carvings, specimens, and occasionally faceting when the material is clean enough.

Traditionally, cordierite has been associated with insight and perspective.

Chemical Composition: (Mg,Fe)2Al4Si5O18

Grade: Semi Precious
Appearance: Transparent
Cracks: Many
Inclusions: Minimal

Approximate Size of 1 pc: 15mm x 12mm x 8mm
Approximate Weight of 1 pc: 3g

Rough is rough. We do our best to grade and describe pieces in the lot, but ultimately, they all differ.