Columbia Gem House Announces New Acquisition of Untreated Sapphires and Rubies from Tanzania
Columbia Gem House (CGH), the gem cutting and wholesale supply house based in Vancouver, Washington, has announced a new inventory of untreated sapphires and rubies sourced from the Winza mining region of central Tanzania. Known for its decades long-standing commitment to mine-to-market, traceable, responsibly sourced gemstones, the family-owned company noted last week that the new material has a beautiful range of color.
Winza
The Winza region is known for producing corundum with high chromium content and good clarity, and the stones in this collection reflect just that. The palette includes saturated pinks, purples, fuchsias, padparadscha, and what CGH describes as “true rubies.” Notably, all the stones are untreated — something that has become less common in the commercial market, particularly for pink sapphire, which is often heated or diffusion-treated to intensify color.
One of the more visually interesting aspects of the collection are the natural bicolor gems, where pink/red and blue areas occur within the same crystal. Some stones reportedly show what CGH refers to as “kaleidoscope” effects — a result of chromophore variation that creates multiple hues within a single gem. While this isn’t the first time such material has come out of Winza, it’s rare to see it presented in this kind of volume.
Most of the stones are offered in calibrated sizes 4.5mm and under, in rounds, pears, baguettes, and marquises. According to the release, CGH’s cutting team prioritized orientation to bring out both saturation and brilliance — something that’s especially important when dealing with untreated stones, which can display more variation than their heat-treated counterparts.
Sourcing for Availability & Traceability
The company notes that the supply chain for this material has been in development for some time, and is consistent with CGH’s sourcing practices more broadly, which have long emphasized ethical origin and documentation.
“Establishing a dependable supply chain for this material has been an important project for us,” says Columbia Gem House’s sourcing team. “This material meets our standards for traceability and offers exceptional quality. We’re particularly excited about offering clean, richly saturated pink sapphire in a market where untreated material is increasingly rare.”
Inventory for the primary color range — pinks, purples, fuchsias, padparadscha — is now available online to registered wholesale buyers. Additional material, including rarer blues and bicolor specimens, is available by request.
While this press release may not signal a major shift in the broader sapphire market, it does offer an example of how some suppliers are working to bring more untreated material into circulation — and how regional mining areas like Winza continue to yield interesting, often underappreciated, corundum.
For jewelry designers and mom & pop retailers looking for small-format stones with natural and unique color, this collection may warrant a closer look.
