Our Metal Refining Process
Testing is done differently based on the product being sold. With most product, we can buy it based on the plumb values. This means you get paid without waiting for a post melt payout. Occasionally with certain items, we might have to do that process of post melt. This is used most commonly with jewelry sweeps, assay required unmarked items and other. If so, we will be there to explain the process and help you through it completely. This usually means we will require a few additional days to provide payout and the information.
There are several ways to determine the precious metal content of products. Using markings found on the product, electronic conducive testing, acid testing and melt assays are just a few of the ways we determine the precious metal content.
Certain methods are more invasive than others. An electronic conducive test will not harm the product in any manner. Acid scratch testing provides testing with no damage to the product to the human eye. Melt testing will completely destroy the product and provide definitive results but at the cost of total destruction of the product.
Acid testing is a method of where two different procedures can take place. One method is not damaging to the product while the other will create burn marks on the product. This is used only if all previous methods are not providing a stable reading.
By rubbing a gold item such as a ring on a black stone, it will leave a distinct gold mark. Since gold is a noble metal meaning it is resistant to change by corrosion, oxidation and acid. A drop of acid made of nitric acid and hydrochloric acid is applied to the mark by karat strength. If the mark remains and is unphased by the acid, it is of that karat or better. Once a certain karat of acid removes the gold scratch, it means that gold karat is within that range.
Electronic Conducive Test
Using an electronic gold tester, an electrical charge is applied against a sophisticated sensor that measures the level of resistance. A display will show how the resistance is translated to karat level. While these instruments are used often and with good results, they are not completely infallible. Things such as stainless steel, zinc gold alloy and other plated items can sometimes present a false positive reading.
We use Kee Gold Testing equipment for one step of our process. While not always perfect, it is one of the best first steps to ensuring gold quality.
Melt assays are what the majority of the refineries do. This is where your product is melted and then the total gold content is determined from the metals in the melt. Some impurities will burn away. After its been melted from jewelry form to a liquid, it is poured into a crucible container. This glob or bar is then assayed for content using XRF or other technology. The downside to this method is that it destroys the product completely. If it melts out differently than you expected, there is nothing that can ben done about that. We are at the mercy of that melt and will have to pay accordingly. Once product has been melted, there is no returns or changes that can be done.