Weighing gold and precious metals requires an accurate and reliable gold scale or jewelry scale. Gold is a relatively rare metal, prized for its glistening appearance and high value. Its malleability enables it to be fashioned into many different intricate forms, explaining its wide use in coinage and jewelry manufacturers. Gold and precious metals, such as silver and platinum, are popular investment choices thanks to their relatively stable value within global markets.
In the buying and selling of gold by bullion traders, jewelry manufacturers, goldsmiths, and jewelry retailers alike, the gold purity and the gold weight are of critical importance. Weighing gold accurately is crucial to both buyer and seller, and is an important part of the sales transaction.
Gold purity can be measured precisely by determining the density of the gold. The accuracy of this measurement also depends upon the accuracy of the jewelry scale or gold scale used to carry out the determination.
Gold Mining And Gold Ore
Before any mining taking place, large quantities of rock are extracted from a potential mine and thoroughly tested. The amount of gold present in the rock determines if extracting the gold ore is financially viable.
This process involves first weighing large samples of the gold ore using a high capacity balance. Small sub-samples are analyzed using refining techniques such as fire assay, which requires the use of a high accuracy analytical balance or a microbalance.
Weighing Gold Bullion
A high capacity gold balance or gold scale is required to weigh bullion in the form of bars or ingots. The London Bullion Market Association (LBMA) specifies that a ‘Good Delivery Bar’ of gold bullion should weigh 400 troy ounces, which is equivalent to 12.4 kg.
METTLER TOLEDO’s high capacity XPR precision balance helps traders fulfill the requirements of LBMA’s good trading practices for good bullion. Built-in quality assurance functions assure accurate results, whilst overload protection safeguards the high-performance weighing cell. Weighing results can be saved on the balance or transferred to a PC or USB stick to ensure traceability. With the dedicated bullion weighing kit, heavy gold bars can be loaded and unloaded with ease.
Gold Jewelry Wholesalers
For weighing larger quantities of gold or for bulk weighing of mass-produced gold jewelry pieces, an accurate high capacity scale is essential. Connecting a printer makes it easy to print out results, avoiding handwriting mistakes, and ensuring an accurate record of transactions.
Gold Jewelry Retailers
Weighing gold accurately is essential to the success of all gold jewelry retailers. Customers must trust the weighing results or the retailer’s reputation will be at risk. Using an extra display so customers can see the weight at the same time provides them with extra reassurance. By connecting a printer, an order ID can be included if required.
The cashier uses the details on the printout when the customer is ready to pay. This simplifies the process for the jewelry retailer and the customer has the confidence of knowing that the transaction has been handled correctly. In retail applications, where a product is sold by weight, the gold weighing process must be Legal for Trade.
METTLER TOLEDO JET jewelry scales and JE jewelry scales have large displays that enable the weight results to be read clearly, even under the bright lights of a jewelry store. METTLER TOLEDO’s jewelry printer simply plugs into the connection at the back of the balance. Also, the JET and JE jewelry scale enable you to connect a printer and auxiliary display at the same time.
Pawn And Gold Buy-Back Shops
Recycling old or unwanted gold jewelry helps to meet the global demand for gold. Pawn and gold buy-back shops use density determination as a first and quick indicator of gold purity. This can be achieved by installing a dedicated density kit onto the weighing pan of a jewelry scale or gold scale by utilizing the under-the-balance weighing functionality.
Here, the jewelry is suspended in a container or liquid below the balance and is a useful method for large and substantial pieces. METTLER TOLEDO JET gold scales and JE gold scales feature a dedicated hook on the base for this purpose.
Gold Purity Or Gold Fineness
Gold is weighed in troy ounces, where 1 troy ounce is equivalent to 31.1034768 grams. However, gold purity, sometimes referred to as gold fineness, is measured in karats (k). Pure gold is 24 karats (24k). Due to the softness of pure gold, it is often mixed with other metals to create a gold alloy when creating jewelry pieces. This gives them a higher resilience to withstand everyday use.
The amount of gold in the alloy is given as the number of twenty-fourths. For example, gold jewelry made from 18k gold contains 18/24 gold (this equates to 75%).
- 24k gold=24/24=100% gold
- 18k gold=18/24=75% gold
- 14k gold=14/24=58.33% gold
- 9k gold=9/24=37.5% gold
Measuring Gold Purity Via Density Determination
Pure gold is a relatively dense material with a density of 19.34 g/mL when measured at 20 degrees celsius. To confirm the purity of an item of gold or a piece of gold jewelry, the density can be measured and the results compared to the density of pure gold.
The density of the item is determined by first weighing the item in air and then again submerged in water. This can be achieved using a dedicated density kit installed on a jewelry scale or gold scale. Alternatively, the item can be weighed first in the air by suspending it below the scale, and then a water bath is raised to cover the item (this method is particularly suitable for large items).
The results of determining density by this process are dependent upon the ambient temperature. This must be adjusted for the density calculation.
Measuring gold purity via density determination provides a quick, first indication of the purity. Further investigations, such as using x-rays, may be required to determine if the jewelry has a fake core. For example, the density of tungsten is comparable to that of gold and can be hidden under the gold alloy.