ASSAY GRADE LEAD FOIL, ASSAY GRADE LEAD TABLETS, SILVER INQUARTS AND COPPER INQUARTS

Assay grade lead, fire assay consumables

We supply  a whole range of assay grade lead foil (assay lead tape), assay lead tablets, silver inquarts and cooper inquarts for cupellation. 

ASSAY LEAD

Our assay lead has low gold, silver and bismuth content, ensuring an exact analysis and also in accordance with ISO11426 for the determination of gold in jewellery alloys.

Indeed, the purity of our assay lead foil (assay lead tape) and assay lead tablets is 99.99%. 99.999% purity lead foil is also available for special analysis where the precious metal content to determine is very low.

SILVER INQUARTS & COPPER INQUARTS

Finally, we also stock 99.99% silver inquarts.and copper inquarts.

ASSAY GRADE LEAD FOIL

Our assay lead foil rolls (assay lead tape) come in various widths and weights.

The thickness of our assay lead foil is 0.1 mm. This ensures an easy wrapping of the sample, and of the silver inquarts.

Furthermore, we can also supply precut assay lead foil. Each precut piece has a weight of 4g and a thickness of 0.25 mm.

ASSAY GRADE LEAD TABLETS

On the other hand, some users prefer assay lead tablets. Our range for lead tables starts at 2g and ends at 10g. 

Using Assay Lead Tablets is particularly convenient because they allow to put a precise quantity of lead in the cupel wihtout having to previously weight them.

 

Lead foil roll
width (mm)Weight (kg)
405
505
5010
7010

Finally, lead foil with a 99.999% purity is also available.

Assay Grade Lead Foil
Assay Grade Lead Foil

Assay Lead Tablets
Dimensions (mm)Weight (g)
Ø 10 x 2,22
Ø 9 x 4,53
Ø 12 x 3,24
Ø 12 x 45
Ø 12 x 66
Ø 16 x 4,410

Assay grade lead tablets
Assay grade lead tablets
SILVER INQUARTS

Our silver inquarts have a purity of 99.99% and each piece has a 500mg weight.  According to ISO11426, it is necessary to inquart to sample to analyse with silver equivalent to 2.3 to 3 times the mass of fine gold present.

COPPER INQUARTS

The copper inquarts are used to analyse white gold alloys containing palladium. 

In this case, traces of palladium may remain in the cornet after a single cupellation and parting. With these alloys, the cornets from the sample and the proof assays should be recupelled with 4 g of lead, silver equal to 2,5 times the mass of gold and with about 50 mg of copper inquart.

Our copper inquarts are in the form of granules allowing an easy weighing.

LEAD SILVER INQUARTS – 2mg Silver (equivalent to Herman inquarts)

Lead silver inquarts consist of precut lead wire with a very definite amount of silver. Furthermore these inquarts are gold free. These lead silver inquarts are equivalent to Herman Inquarts and can replace them.

The main advantages of using Herman Inquarts are:

– HIgh precision as each inquart contains an exact amount of silver 

– Very fast addition of the silver in the crucible as it is not necessary to weight (time saving) 

SilverLeadTinArsenicIronAntimonyCadmiunGoldIndiumBismuth
5%95%0.1ppm0.2ppm0.1ppm<0.1ppm0.1ppm<0.1ppm0.1ppm<0.2ppm
Lead Silver Inquart Typical Composition

Lead silver inquarts - 2mg Ag (Herman Inquarts)
ASSAY LEAD IN CUPELLATION

The recommended quantity of assay grade lead for cupellation is about 20 grams of lead for every gram of gold. However, when analysing white gold it is necessary to double this lead quantity. In addition to that, ISO11426 recommends using Magnesium Oxide Cupels, usually of diameter 22 mm to absorb 6 g lead, or of diameter 26 mm to absorb 10 g lead, or blocks of cupels of similar absorption. This is equivalent to our cupel nº 4A or to any of our blocks.

 

When the cupel is placed in the oven, the lead melts, and due to the oxidising conditions, it transforms into litharge (PbO). This newly formed litharge acts as a “solvent” of all the other oxides formed during the cupellation, and is absorbed by the cupel.