Damaged cylinder on used refractometer??

[ColinMartin]

I bought this refractometer used on ebay (with no return allowed) and the prism cylinder looks like it has white, dried gunk on it. Can this be cleaned or is it damaged? I've taken online gemology classes but this is the first time I've seen a refractometer in person.

Thank you for your time.

 

[mastercutgems]

Hello;

Looks like the hemicylinder may have had RI fluid left on tooooooo long and they scratched it trying to remove it ??? I would first try denatured alcohol and if that did not do it; you may be able to remove some of it with cerium oxide to try and polish it away??? I know it is more-than-likely glass or similar with a mohs of 6 but I know they make them in cz which is around 8 to 8.5. If you choose to try and clean the hemicylinder with a tiny amount of cerium oxide powder polish I would use a small amount of mineral oil and a Q-tip and be gentle.

Also you can look around and I think you can just buy the replacement hemicylinder for them. Also after basic cleaning try it out on a known material and see what it reads ; many times the junk is above or below the critical area of reading??? worth a shot.

Also IGS has a article on the subject https://www.gemsociety.org/article/re-polish-refractometer-hemicylinder/

Sorry it happened to you.

Most Respectfully

Dana Reynolds
ASG Certified
Supreme Master Gem Cutter
#96cge42