Loss of weight on a repolish

[stebbo]

If anyone out there has done or witnessed a lot of repolishes, what''s seems to be a typical range of weight loss, say for a single carat diamond?

 

[DiamondExpert]

Impossible to answer without knowing (in detail) the reason for the repolish or the defect to be corrected.

 

[stebbo]

I was hoping a typical range might cover that, but let''s consider buy-backs and trade-ins where the vendor wants to bring the polish back up to match the lab report. I could imagine over the years the vendor might conclude that many times no repolish was needed, sometimes the repolish saw no weight loss worth affecting the buy-back price, and the rest of the time we had to lower the buy-back price because of a non-trivial weight loss.

I realize there are extreme cases, but could a vendor give a client a rough idea as to range of how many (milli)points are typically lost?

 

[denverappraiser]

The usual reason for a vendor to repolish a stone on a buyback is to repair minor nicks and bruises that have developed with wear. It’s a complicated question to decide if it’s worth the money and risk to take a stone to the wheel and there’s no short answer without inspecting the stone.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[oldminer]

I have had many diamonds, old cuts, repolished which lost virtually no weight. Now, I was not attempting to recut or reform them. It was just to get off a tiny nick or fix a few abrasions. I have seen 1.00ct diamonds which weight 1.003 still weigh 1.001 after a delicate repolish.

Usually, when I actually own a diamond weighing 1.003 and have it re-polished my luck makes it come out 0.998..... Maybe someone else is just luckier.

Polish rubs the surface to a luster and removes virtually no material.

A repolish on a sapphire or an opal does remove more weight since they are softer and just rub away more rapidly.

 

[stebbo]

Date: 8/28/2007 8:29:42 AM
Author: denverappraiser
The usual reason for a vendor to repolish a stone on a buyback is to repair minor nicks and bruises that have developed with wear. It’s a complicated question to decide if it’s worth the money and risk to take a stone to the wheel and there’s no short answer without inspecting the stone.

I see, so it's more about nicks than a coverage of scratches like the alloy in a band would show - I get it!

Date: 8/28/2007 11:08:24 AM
Author: oldminer
I have had many diamonds, old cuts, repolished which lost virtually no weight. Now, I was not attempting to recut or reform them. It was just to get off a tiny nick or fix a few abrasions. I have seen 1.00ct diamonds which weight 1.003 still weigh 1.001 after a delicate repolish.

Great info. Thx.

Date: 8/28/2007 11:08:24 AM
Author: oldminer

Usually, when I actually own a diamond weighing 1.003 and have it re-polished my luck makes it come out 0.998..... Maybe someone else is just luckier.

Where's that positive attitude....