Authenticate your 1 oz Gold Australian Kangaroo

How to spot a fake Australian Gold Kangaroo

The Australian Gold Kangaroo is struck by the Perth Mint in 99.99% pure gold. It began in the late 1980s as the Gold Nugget, with a different gold nugget on the reverse, and switched to a kangaroo design in 1989. The kangaroo design has changed many times since, which is useful for spotting fakes: a counterfeit sometimes pairs the wrong design with the date.

What fakes exist

Gold-plated base metal. Brass or copper with a thin gold layer. These are usually clearly underweight or the wrong size.

Tungsten-core fakes. Tungsten is almost as dense as gold, so a tungsten centre covered in gold can come close to the correct weight. These are made to pass a scale.

Cast fakes. Poured into a mould rather than struck. Look for a grainy or porous surface, soft details and a seam on the edge.

Struck counterfeits. Made on a press with copied dies. Details can be close to genuine, but the metal, weight or dimensions are usually off somewhere.

The checks, in order

1. Weight

A 1 oz Gold Kangaroo contains one troy ounce of fine gold, 31.10 g. Use a scale that reads to 0.01 g.

• Plated base-metal fakes are usually several grams light.
• A coin more than a few hundredths of a gram off, without damage to explain it, should be tested further.
• A correct weight does not prove the coin is genuine; tungsten-core fakes are made to pass this test.

2. Diameter and thickness

Measure with digital calipers and compare with the facts box on this page. To hit the right weight with a lighter metal, a fake has to be thicker or wider, so weight and dimensions together are much harder to fake than either alone. Check thickness at several points; uneven thickness is a warning sign.

3. Obverse

Use a 10x loupe. Coins from the reign of Queen Elizabeth II carry her portrait; more recent coins carry King Charles III. Check that the portrait matches the date.

• Hair, crown and facial details should be sharp, not mushy.
• "ELIZABETH II" or "CHARLES III", "AUSTRALIA" and the face value ("100 DOLLARS" on the 1 oz) should be crisp and evenly spaced.
• The fields should be smooth and clean. A grainy or rough background suggests a cast fake.

4. Reverse

• The kangaroo should show sharp fur texture and muscle definition, with a clear eye.
• Background details (grass, sun, landscape) should be clean, not blurred into a mass.
• The date, weight and purity inscription and "P" mint mark should be cleanly struck.
• The design must match the year. Compare against the Perth Mint's images for that year, or a reference such as the NGC or PCGS price guide. A wrong design for the date is a strong sign of a fake.

5. Edge

The edge is reeded. Reeds should be evenly spaced, with consistent depth all the way round and a clean meeting with both rims. Uneven or flat-topped reeds, pits, or a seam running around the edge are common signs of a fake. Rolling the coin slowly while watching the edge at eye level makes irregularities easier to see.

6. Magnet

Gold is not magnetic. Hold a strong neodymium magnet near the coin. Any attraction means steel or iron inside, and the coin is fake. Passing only rules out ferrous metal; brass, copper and tungsten are not magnetic either.

7. Ping test

A genuine Gold Kangaroo gives a clear, sustained ring when balanced on a fingertip and tapped gently with another coin. A coin with a different metal inside usually resonates differently, because metals such as tungsten are much stiffer than gold. The ping test at the top of this page listens for the coin's resonant frequencies and compares them with a genuine Gold Kangaroo.

Treat it as one strong check among several. Background noise, how the coin is held, damage or a capsule can throw it off, and some fakes may not be caught. If the result disagrees with your other checks, take the coin out of its capsule and repeat in a quiet room.

8. Further testing

• Specific gravity: weighing the coin in air and in water gives its density, which for pure gold is about 19.3. Plated base metal reads far lower, though a tungsten-core fake can come close.
• Electromagnetic testers (such as the Sigma Metalytics) check conductivity below the surface and help with tungsten-core and plated fakes.
• XRF at a dealer confirms the surface is pure gold, but cannot see a core underneath.

Combining several of these is far more reliable than relying on one.

Date and variety tells

• Nugget or kangaroo: early coins show a gold nugget on the reverse; from 1989 the reverse shows a kangaroo. Both are genuine, but a nugget design with a later kangaroo-era date, or the reverse, is wrong.
• Portrait: Elizabeth II on earlier coins, Charles III on later ones. The portrait must match the year.
• Don't confuse products. The Perth Mint also makes silver and platinum Kangaroos and many proof and special issues. A silver Kangaroo is a much larger coin; make sure you are comparing against the right product.

Graded coins and dealers

A coin graded by PCGS or NGC has been examined by experts, which helps for older or scarcer years. Fake slabs exist, so look up the certificate number (PCGS, NGC) and make sure it matches. Buying from the Perth Mint or an established dealer with a returns policy, and testing on arrival, removes most of the risk. Be wary of prices well below what reputable dealers charge.

If you suspect a fake

1. Stop. Don't buy it, and if you already own it, don't sell or trade it on.
2. Weigh and measure again, and repeat the ping test in a quiet room.
3. Compare with a Gold Kangaroo you know is genuine, ideally of the same year.
4. Take it to a reputable dealer for electromagnetic or XRF testing, or send it for professional authentication.
5. Keep your purchase records and photos, and contact the seller with your evidence to ask for a refund. If you paid by card, your card provider may also be able to help.

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