Duncan Miller





These are the rhodochrosites (presumably from Hotazel) that I have been faceting, on and off, for the past two months. The ‘pink’ stones (on the left) are 0,65 ct; 0,68 ct; 1,46 ct; and 0,96 ct.  The ‘red’ stones (on the right) are 1,39 ct; 1,66 ct; and 1,71 ct. The rough was acquired more than twenty years ago as a small batch of broken and half-finished stones. A recent article about faceted rhodochrosite in The Journal of Gemmology inspired me to try to resurrect them. Dopping was not problematic, using low-temperature green jeweller’s wax. Cutting the facets I did on a copper lap with 3000 mesh diamond. Polishing was on a speciality lap from Gearloose.co with 100 000 diamond, and lots of trial and error to find an effective combination of diamond paste, lubricant, rotational speed and direction. Rhodochrosite has three directions of perfect cleavage, so each facet became its own adventure to avoid pitting, chipping and scratching. Some residual scratches remain because trying to polish them out simply made them worse. 

(These stones have already been snapped up by two different purchasers. Definitely special stones by a special cutter! Ed.) 

Here is a direct link to one of the Mindat articles about mineral properties to illustrate what Duncan means about his rhodochrosites having rhombohedral cleavage:

https://www.mindat.org/article.php/2898/Determining+Fracture+and+Cleavage+in+Minerals