The cup was spotted by an eagle-eyed shopper (Getty).
In a real case of one man's trash being another man's treasure, a $4 op shop find has sold for more than $75,000 at auction.
Sotheby's Australia sold the 17th century Chinese "libation cup" carved from rhinoceros horn for $75,640 last week on behalf of an anonymous op shop scourer.
The lucky seller spied it in a Sydney shop and after doing some research he sent photos to Sotheby's consultant Ann Roberts, a specialist in Asian Art, who confirmed that it was indeed rare and valuable, Fairfax reports.
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Despite some damage to the cup, she gave it a pre-sale estimate of $20,000 to $30,000. It went for more than double.
The cups are especially prized by Asian collectors, although objects made from materials such as ivory and rhinoceros horn are subject to a CITES licensing restrictions before they can be sent overseas.
Mrs Roberts told Fairfax "He (the buyer) was very pleased".
Finding such a valuable item in an op shop is not to be expected but she said she wasn't surprised it had been given such a token value.
"They don't look immediately attractive to the untrained eye," she said.