Cast Bar
Also: Poured Bar, Cast Ingot
A cast bar is made by pouring molten precious metal into a mould, which on cooling leaves the characteristically rough, slightly irregular surface.
A cast bar is the oldest and technically simplest way of turning precious metal into a tradable investment product. In casting, metal that has been melted in a crucible or induction furnace — usually gold or silver with a fineness of 999 or higher — is poured into a steel mould. Once it has cooled naturally, the solidified blank is removed, cleaned and stamped with the maker's mark, the fineness and a serial number. The result carries a slightly uneven, often wavy or crystalline surface — an unmistakable visual cue that tells a cast bar apart from a minted bar at a glance.
The production process in detail
The workflow breaks down into four stages:
- Melting – raw granules, recycled material or doré is brought to melting temperature in the furnace (gold: about 1,064 °C, silver: about 962 °C).
- Pouring – the melt is poured into a pre-warmed steel mould to avoid cracking from thermal shock.
- Cooling and removal – the bar cools in a controlled way, shrinks slightly and is then lifted out.
- Stamping and testing – the refinery or maker impresses the fineness, weight, maker's mark and serial number, followed by spot checks on weight and fineness.
Cast versus minted bars
| Feature | Cast bar | Minted bar |
|---|---|---|
| Surface | Rough, slightly irregular | Smooth, can be mirror-polished |
| Production effort | Low | Higher (rolling, punching, striking) |
| Typical premium | Lower | Higher |
| Anti-forgery | Serial number + weight | Serial number + fine struck detail |
| Storage | Loose or blister | Often blister / assay-card bar |
| Appeal | Industrial | Sometimes collectible |
The lower premium (agio) makes cast bars especially attractive to investors who want the metal content as close to the spot price as possible. The melt value calculator lets you work out a bar's pure material value at any moment.
Weight classes and well-known makers
Cast bars come in a wide range of weights. In gold, sizes from 1 g up to 1 kg dominate; the kilo bar is the standard size for institutions and wealthier private investors. In silver, 100 g, 500 g and 1 kg cast bars are common, while wholesale trade favours 5 kg and 15 kg bars.
Among the best-known makers are Heraeus (Germany), Umicore (Belgium), PAMP Suisse (Switzerland), Valcambi (Switzerland) and Argor-Heraeus (Switzerland). Bars from respected refineries generally resell without difficulty, provided the serial number and stamp are intact.
Authenticity testing and storage
Because of the uneven surface, careful checking matters with cast bars. Reliable methods include:
- Weight check – deviations of more than ± 0.1 g on small bars are a warning sign.
- Density test (Archimedes' principle) – gold has a density of 19.3 g/cm³; a clear deviation suggests adulteration (e.g. tungsten).
- X-ray fluorescence (XRF) – non-destructive, precise fineness determination.
- Ultrasound testing – detects cavities or inclusions inside the bar.
If you store cast bars at home, leave them in their original packaging to avoid surface contact that can cause scratches or chemical reactions. You can use the interactive coin authenticity check for basic physical tests, and the buying price calculator to gauge resale value.
Note: any comments on tax matters (e.g. VAT exemption, capital gains) are not tax or investment advice.
In short
Cast bars give investors a low-cost, hard-to-forge and globally tradable form of physical metal ownership, with a low premium and good liquidity. Their raw appearance is not a defect but the direct result of the oldest bar-making method in the world.