1937 Australian one crown silver

You now know what to look for to spot those particular types of replicas, but the only way to have confidence in telling fake from fair dinkum is to become very familiar with the genuine article. Lacking that, your best bet is to buy from a trustworthy source.

Just as the best place to buy genuine US coins is to buy from American sellers, the best place to buy Australian coins is from Australian sellers. If you want to go that route, you might want to try starting a thread in the "wanted to buy" section, with a link to this thread. Some of the Aussie members here might be happy to help you out (sorry, I don't have a spare one at the moment). 1937 crowns are typically trading at around AU$25 to $30 each here in Australia.

As for general tests of genuineness, I can only offer the usual list given for any type of coin: weight, magnet, specific gravity, edge, appearance. If they all match, then it's a reasonable chance the coin is genuine; while a fake coin can appear to match all of these, it just isn't worth the counterfeiter's while to do so for a coin with as little numismatic value as the '37 crown.

And, Also look out for a 1938 crown too. But being much smaller mintage fetch much higher price -going for arount $120 to $150 on eBay presently.
I am negotiating for an old lot of coins from a deceased estate and mostly nothing special but there is a 1938 crown. If I get the lot I will probably sell off most but....do I keep the crown or sell it

Jeff

I used to think they weren't worth faking, not valuable enough, until someone pointed out that in 1937, they were probably worth faking.

sharing the pics of the 1937 replica obtained equivalent of us$1 for the learning process:
it is silver-plated, I scraped it off at the Rev, it can be magnetized, has no mintmarks, bad overall texture on closeup, a lot of casting small "pimples" and feels greasy to the touch

I now bring a small weak magnet and 10x magnifying glass, whenever attending a coin dealer's fair.