The Gold Refining Process

Recycling is extremely important for the precious metals industry. In fact, recycled gold makes more than a third of the current world supply. Here at Manhattan Gold & Silver we are pleased to be one of the few companies with the flexibility to offer precious metal refining services to a variety of businesses—from jewelers of all sizes, to pawnbrokers, dentists, and more.

The process begins when a client brings us scrap gold to be recycled. To determine the purity of the gold, we perform an assay or test. Depending on the size of the lot and type of scrap it contains, we may do an acid, XRF, ultrasound, or fire assay.

  • For the acid (AKA scratch) assay, we scratch a piece of the gold against a basalt stone, marking it. By applying certain strengths of nitric acid to this mark and measuring the resulting reaction, we can accurately measure the purity of the gold.

  • For X-ray fluorescence (XRF), a gold sample is placed in one of our two machines. The XRF machine bathes the sample in X-rays, causing the sample to emit light (fluorescence) at an energy level specific to its atomic structure. The machine analyzes this energy level and determines the amount of pure gold within the sample.

  • For the ultrasound assay, we use a special machine that sends an ultrasonic pulse through a sample and measures the frequency for changes. If the consistency of the metal changes, so does the frequency. This makes the ultrasound assay perfect for determining whether an item is precious metal-plated without damaging it.

  • For large lots of scrap, we recommend the fire assay. This test is extremely accurate, but time consuming because the gold is melted down and specially processed.


Once we have determined the weight and purity of the gold, we have all the information we need to quote you a payout price. From there, your gold is melted down and recycled (you can watch if you want). This infographic explains how we recycle gold every day here at MGS.


Platinum and Glassmaking

From an industrial standpoint, platinum is tough stuff. It has excellent resistance to corrosion, has stable electrical properties, and is stable at high temperatures. How high? Platinum’s melting point is 3214.9 °F. If you’re tooling around with heat, platinum is your go-to metal. That’s why it’s a critical element in all things glassmaking.

Glassmaking materials are heated in excess of 3000 °F. This means that the tools and vessels that hold, channel, and form the molten glass must be extremely heat resistant. Fortunately, platinum and platinum alloys do not oxidize or scale at high temperatures. Some glassmaking applications use platinum-rhodium alloy for added resistance to corrosion at high temperatures.

One of the most “platinum-intensive” types of glassmaking is for reinforcement glass fiber. Molten glass is held in a platinum-rhodium container. The base of the container has precision shaped holes through which the glass is drawn to create extremely thin fibers. The glass fibers are used to reinforce other material types, like glass reinforced plastic, aka Fiberglass.

However, some glassmaking processes require pure platinum – such as those for optical and ophthalmic glass. These types of glass are used for telescopes, binoculars, eyeglasses, etc. As such, they must be perfectly clear and free of defects. During heat treatment, rhodium may add unwanted color to the glass. Since pure platinum won’t react with molten glass, that makes it the material of choice for creating perfectly clear lenses.

What is the Borg-Warner Trophy Made of?

Ladies and gentlemen, start your engines! The events for the Indianapolis 500 are already underway, and by the end of the month, there will be a new champion worthy of addition to the famous Borg-Warner trophy – an award with truly awe-inspiring precious metal design. 
   
Commissioned by automotive supplier BorgWarner , the trophy is relatively massive, standing at about 5’ 4” and weighing almost 153 lbs. It used to be light enough to be carried by the winner of the Indianapolis 500, but additional bases added over the years to accommodate new winners have increased the weight. Size aside, one of the most impressive design aspects of the Borg-Warner is that it has bas-relief sculptures of the likeness of each driver who has won the race since the trophy’s inception in 1911.

The entire trophy is covered with hundreds of racers’ faces, next to inscriptions of their name, victory year, and average speed during the race. The alternating faces and inscriptions create a checkerboard pattern – just like the iconic racing flag. Tradition dictates that repeat winners of the Indianapolis 500 get a new likeness sculpted onto the trophy – common variations include the addition or removal of racing headgear, like helmets and goggles.

The trophy is entirely sterling silver, with the exception of the likeness of Tony Hulman (owner of the Indianapolis Motor Speedway from 1945-1977) – which is gold. Of course, the trophy isn’t actually awarded to Indianapolis 500 winners. Champions instead receive an 18” tall replica of the trophy dubbed the “Baby Borg.” The replica only features the likeness of the winning driver.