About us

River Gemz specialises in expertly hand-crafted jewellery made from quality natural Australian solid
opals, cut into freeform shapes to maximise their unique attributes.
River Gemz is in the picturesque town of Mannum, along the banks of the beautiful Murray River in South Australia.

Visitors to River Gemz can:

Expect honest and expert guidance

Purchase quality jewellery or unset opals

Receive opal valuations

Obtain 1-1 lapidary advice

Observe the cutting and polishing process occurring in the workshop

River Gemz opened in October 2022 and is operated by a brother and sister team. The siblings are Finnish born Australians who moved to Australia in 1970 with their family.


Harri Mäenpää

Harri Mäenpää has been involved in the opal industry since 1991 and is the River Gemz lapidarist. He has a genuine passion for working with opal. His opal journey commenced in the Mintabie Opal Fields where he mined for 13 years with his father. During this time, he learned where opal is formed and how it can be extracted. From mining he turned to cutting opal, perfecting his craft with a master cutter in Coober Pedy.

For a decade [2004-2014] Harri sold the fruits of his labour in the market stalls of far North Queensland. He then co-established ‘Opal Time’ in Kuranda. Harri and his business partner ran this successful enterprise together for 8 years before Harri relocated to South Australia in 2022.

Marjut Mäenpää

Marjut Mäenpää is the marketing manager, responsible for the social media and online shopping part of the business. She is awed by her brother’s extraordinary opal cutting and jewellery design skills and enjoys show casing his work at the shop or via various digital marketing platforms.

Marjut successfully transformed and integrated her 31 years of experience as a secondary school mathematics teacher, utilising her skills to resolve challenges that an online presence can manifest.

She loves interacting with River Gemz customers to share some interesting facts about Australia’s national gemstone.

Nano - Canine Customer Relations Specialist

River Gemz is a proud family business which also includes Nano-Second, the 3-year-old Labradoodle who makes sure that all guests are warmly embraced.

Harri, Marjut and Nano-Second look forward to welcoming you.