Bone ash vs Magnesite

[GoldGuy]

Please help me out here, what is the results difference in a au/ag fire when using either a bone ash cupel or a magnesite cupel.

And maybe I should be using one or the other for different scenarios and what would those be.

Stupid in Wisconsin,

GoldGuy

 

[fireguy]

Hi GG:
This is mainly a question of preference. Many old-time assayers swear by bone ash cupels, and they do have the advantage of working with a slightly lower temperature (maybe 50 degres F less) than MgO. But they have the disadvantage of being softer, much more expensive, and more fragile.

When we used Mabor MgO cupels for bullion analysis, we had excellent results (never lost an umpire). This may be due to greater consistency (even if the actual loss is higher).

But, if you prefer bone ash, and have better results, and can stand the price...

More information on both types here:

http://www.Lmine.com/go.mvc?id=cupels

 

[JonSnow]

Because of the volume of assays we put through, we use MgO. They are very good cupels. Our Standard Reference Materials test are within the +/- reported. We do keep a few cases of bone ash cupels in stock as once in a while a customer will request them for their assay. (Thinking they will get better results)

 

[devan]

We use MgO, as well. Price and durability are the main selling points. We ran many internal tests using both Bone Ash and Magnesite cupels, with no difference in results.