Dion Jacobs was backfilling a trench at Lilydale when something caught his eye.
At first he thought it was a washer.
But on closer inspection he realised it was something far more important.
In other news:
"Something caught my eye. I thought it was a little button [so] I picked it up," Mr Jacobs said.
"It was actually a little pendant that someone would wear around their neck. It had writing on the back and an RAAF emblem on the front."
After cleaning the pendant Mr Jacobs noticed the date 1942 inscribed on the back along with a message.
"It stated 'to mother from Geoff with love the 10th of the fifth 1942'," he said.
"He obviously received that while the war was happening - World War II - got it inscribed and sent it back to his mother."
Not knowing where to start in returning the pendant back to the rightful owner Mr Jacobs turned to social media.
He posted on the local community page and was soon put in touch with the Lilydale Historical Society.
"I got messages, phone calls through Messenger and people pointing me in the right direction," he said.
"[They said] it would have been a man named Geoffrey Arnold because the Arnold's were one of the main families who started up Lilydale."
One month after finding the pendant Mr Jacobs was able to return it to Geoffrey Arnold's granddaughter.
Andrea White said she was in shock when she found out someone had found her grandfather's locket.
"I couldn't [react] in any way really because it was just a shock after all these years," she said.
"The history and everything I love [and] my daughter loves it even more."
Mr Jacobs said it was amazing to be able to reconnect the family with their history.
"It is something I don't reckon I am ever going to forget," he said.
"Geoffrey Arnold will be etched in me for quite a number of years after finding it, doing the research and meeting all the family as well."
He thanked everyone who helped with the search, especially Bettie Vinnie from the Lilydale Historical Society.