How to Estimate Gold Content in Gold Plated Parts
When trading electronic scrap or jewelry, we sometimes have to quote plated materials.
When the material is homogenic, we can estimate in 3 main ways:
- The most accurate way is taking a sample, dissolving the gold in a solution, precipitating it and
then casting the precipitated gold. This is actually a refining process (which is more complicated and
not suitable for everyone). You can learn more in this video.
- In case the plated materials are brass or copper it is possible to cast a sample and analyze it with “Fire Assay” or XRF to identify the gold content.
- A less accurate but quick method, is estimation of gold content by the thickness of the gold-plated parts. This method is limited in its accuracy due to non-homogenous coating layer, and the
difficulty in estimating surface area. However, it can enable getting an idea about gold content by
using following formula: X = (1000/W) x S x T x 19.3
X = Total gold in gram / per Kg scrap
W = Part weight in grams
T = Thickness of plated material in cm (XRF test)
S = Estimated surface area of the part in cm²
Ƥ = Gold density 19.3 g/cm² (constant)
Example:
We have a ball with a diameter of 0.5 cm, weight of 0.6 g and thickness of 2 µm.
We calculate:
S = π D² = 3.14 x 0.5² = 0.785 cm²
T = 2 µm = 0.0002 cm
W = 0.6 g
X = Total gold in gram per 1 Kg Scrap = (1000/0.6) x 0.785 x 0.0002 x 19.3 = 5.05 gr/Kg
Gold plated thickness can be analyzed with XRF (some XRF does not have this application).
For your convenience, please use our Calculator
* Note: 1 µm = 0.0001 cm
A.G. Metals is a leader in the field of precious metals, with over two and a half decades of experience specializing in the trading & recycling of precious metals.
Ami Gur
A.G. Metals Ltd.