"It just about blew my eardrums off, so I thought I better check that."
Bending over, he noted a gap in the creek bed, suggesting a ready trap for something heavy, and stretching down and lifting off two large rocks, "I noticed a yellow outline".
"I almost walked straight past where it was. I thought it was more a spot where old coins or bottles would get stuck. It [the nugget] was literally just sitting in bedrock up a creek. I wasn't expecting to find anything like that. It just happened," Mr Douglas said.
"I nearly had a heart attack when it came out of the ground. I fell over against the bank and it took a little bit for my brain to catch up with what I was seeing."
Douglas said he could hardly believe his luck.
"I had cellphone reception, so I rang my mother and said, 'You'll never guess what I just found.' I was shaking. I was lost for words."
He had since been advised by two gold buyers in Westland that it was the biggest they had seen since a 14oz nugget from the Paparoa Range area turned up about 1979.
Douglas' windfall was valued at $12,500 in weight value, and $25,000 as a display piece.
He has been using his metal detector for nearly a decade, collecting old goldfields relics, pick heads, coins, bullets, the remnants of a rifle, and the odd bit of gold.
By late Wednesday, an anonymous gold buyer from Canterbury had snapped up the nugget, which was destined to be displayed in a private collection.
The price he paid, like the discovery site, was undisclosed.
