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Thesis Gems and Jewelry

From the San Francisco Bay Area of California, Thesis Gems is the epitome of modern luxury: mine-to-market and transparent, crafting stylish pieces for all occasions. Women-owned, this artisan brand sources pearls, diamonds, rubies and more with the utmost respect for their source – with fashion-forward results.

Founder Cate Claus has been studying gemology, jewellery fabrication, and the global history of mineral extraction for years in order to establish sustainable and transparent sources for her select gemstones.

Their pearls are sourced from Sea of Cortez in the Gulf of California, and from Kasumi pearls in Japan, both small and sustainable productions that have restored the marine environment from which they are harvested. Tsavorites are from Bridges Tsavorites in Kenya, a fully integrated mining company that offers health insurance for its workers and employs ecological practices such as the collection and reuse of rainwater. Diamonds are either certified Canadian diamonds or fine certified re-cut post consumer diamonds from Perpetuum Jewels.

Moreover, Sapphires are sourced from Sheahan Sapphires and come from Sri Lanka, directly mine-to-market. Their solid opals are from Hopkins Opals, sourced directly from Lightning Ridge, Australia, which follows strict mining protocols including restoration of the land after mining has commenced. Mozambique rubies are sourced from Gemfields, whom are committed to sustainable mining practices for both workers and the environment.

The brand thinks daily about ways to support ecological conservation and fair labor mining processes in the sourcing of the gems they use in their heirloom jewelry. In addition to being a member for 1% for the Planet which supports California Waterways where Thesis Gems is based, they are constantly looking to establish relationships with conservation and restoration organisations in the countries from which the gems originate.


Thesis Gems and Jewelry has been awarded the Butterfly Mark for their measurable impact and company-wide commitments to sustainability.

Want to learn more? Click on the interactive Butterfly Mark on your left and scroll through each Positive Action to read a short description of the brands efforts and achievements as verified by Positive Luxury. You will also be able to find the interactive Butterfly Mark online on the brands website, retailer and partner sites.

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