The Leederville jeweller, an industry team leader for the campaign that raises money for breast care nurses, used two amethyst gems and diamonds to create the pendant, worth more than $6000.
Mr Milne said getting the shape right was the most challenging part of the project.
"The gallery on the side I opened up a little more than I was going to, so the amethysts will absolutely pop," he said.
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READ NOWMr Milne said a robust but plain 18-carat white gold chain would complete the hourglass-shaped pendant, made with help from Community Newspaper Group. The pendant is on display at Rohan Jewellers, Oxford Street, Leederville.
Breast Cancer Care WA (BCCWA) founder Ros Worthington launched the campaign, which encourages employees across the state to donate an hour's wage to the cause on International Women's Day.
"Increased funding thanks to the Buying Time campaign will help us grow the number of people provided with care, and help us support more families and carers affected by breast cancer," BCCWA chief executive Zoe McAlpine said.
"Breast Cancer Care WA needs to raise $2 million per year to fund its current level of service."
Donations will be shared between BCCWA and the McGrath Foundation. Visit http://buyingtime.gofundraise.com.au.