Cast Bar
Also: Poured bar, Cast Bar
A cast bar is produced by pouring molten precious metal into a mould, which after cooling leaves a characteristically rough, slightly irregular surface.
A cast bar is the oldest and technically simplest form of processing precious metal into tradable investment products. In the casting process, the previously melted precious metal - usually gold or silver with a fineness of 999 or higher - is poured into a steel mould from a crucible or induction furnace. After natural cooling, the solidified raw bar is removed from the mould, cleaned and provided with the manufacturer's stamp, the fineness and a serial number. The result is a product with a slightly irregular, often wavy or crystalline surface - an unmistakable visual identifying feature that distinguishes the cast bar at a glance from the minted bar.
Manufacturing process in detail
The production sequence can be divided into four steps:
- Melting - raw granules, recycling material or dore material is brought to melting temperature in the furnace (gold: approx. 1,064 C, silver: approx. 962 C).
- Casting - the melt is poured into a preheated steel mould (ingot mould) to avoid cracks from thermal shock.
- Cooling & removal from the mould - the bar cools in a controlled manner, shrinks minimally in the process and can then be removed.
- Stamping & testing - the refinery or manufacturer stamps in the fineness, weight, manufacturer's mark and serial number; a random weight and fineness check follows.
Cast vs. minted bar
| Feature | Cast bar | Minted bar |
|---|---|---|
| Surface | Rough, slightly irregular | Smooth, mirror-polished possible |
| Manufacturing effort | Low | Higher (rolling, punching, minting) |
| Typical premium | Lower | Higher |
| Counterfeit security | Serial number + weight | Serial number + fine minting details |
| Storage | Loose or blister | Often blister / certified bar |
| Collectible value | Industrial | Partly collectible |
The lower premium (agio) makes cast bars particularly attractive for investors who want to acquire the metal content at the closest possible price near the spot price. The melt value calculator helps to determine the pure material value of a bar at any time.
Weight classes and common manufacturers
Cast bars are available across a broad range of weights. For gold, sizes from 1 g to 1 kg dominate; the kilo bar is regarded as the standard size for institutional and wealthy private investors. For silver, 100 g, 500 g and 1 kg cast bars are widespread, while in wholesale 5 kg and 15 kg bars are common.
Among the best-known manufacturers are Heraeus (Germany), Umicore (Belgium), PAMP Suisse (Switzerland), Valcambi (Switzerland) and Argor-Heraeus (Switzerland). Bars from renowned refineries can generally be traded without difficulty on resale, provided the serial number and stamp are intact.
Authenticity testing and storage
Because of the irregular surface, careful testing is important with cast bars. Proven methods are:
- Weight check - deviations of more than +/- 0.1 g in small bars are a warning sign.
- Density measurement (Archimedes principle) - gold has a density of 19.3 g/cm3; significant deviations indicate adulteration (e.g. tungsten).
- X-ray fluorescence analysis (XRF) - non-destructive, precise fineness determination.
- Ultrasonic testing - detects cavities or inclusions inside.
Anyone storing cast bars at home should leave them in their original packaging to avoid surface contact that can cause scratches or chemical reactions. Investors can additionally use the interactive coin authenticity check for basic physical checks; for the purchase price on resale the purchase price calculator is recommended.
Note: information on tax aspects (e.g. VAT exemption, holding periods) does not constitute tax or investment advice.
In brief
Cast bars offer investment buyers an inexpensive, counterfeit-secure and globally tradable form of physical precious metal ownership - with a low premium and high liquidity. Their characteristic raw appearance is not a quality defect but the direct result of the oldest bar-casting process in the world.