Diamond Foundry
Company
Key facts about this entity
- Founded 2012; headquartered in the San Francisco Bay Area
- Products: lab-grown single-crystal diamonds; diamond wafers for chip cooling in development
- April 2021: $200 million led by Fidelity at $1.8 billion post-money (last priced round)
- November 2025: Spain's SETT to invest about €753 million for about 32 percent of a wafer-plant joint venture in Trujillo
- TUM link: CEO Martin Roscheisen, TUM bachelor's degree (1992)
- Listed on TUM's 'Unicorns founded by TUM alumni' list (dated 4 August 2026) as operational
Entity Profile
Overview
Diamond Foundry grows single-crystal diamonds in plasma reactors. It sells lab-grown diamonds for jewellery and is developing single-crystal diamond wafers intended to draw heat away from semiconductor chips.
Why this entity matters
Diamond Foundry is on the Technical University of Munich's August 2026 list of unicorns founded by TUM alumni, supplied to Startuprad.io by UnternehmerTUM's press office in October 2026. Its CEO and co-founder Martin Roscheisen holds a bachelor's degree from TUM (1992). In 2025 it became relevant to European industrial policy when Spain's state technology fund agreed to back a diamond-wafer plant in Extremadura. No UnternehmerTUM programme or UVC Partners investment has been documented.
Company history and product
Founded in 2012, Diamond Foundry raised a $200 million round led by Fidelity in April 2021 at a $1.8 billion post-money valuation, its last priced equity round. In November 2025 Spain's state technology fund SETT agreed to invest about €753 million for roughly 32 percent of a joint venture building a synthetic diamond wafer plant in Trujillo, part of a project of about €2.35 billion through 2029. Lab-grown diamond prices have fallen sharply since 2021, so the April 2021 valuation is dated.
Role in the European start-up landscape
Diamond Foundry is a US company. Its link to Europe runs through its TUM-educated CEO and the Spanish wafer project.
Selected relationships and affiliations
Founders: Martin Roscheisen (co-founder, CEO), Jeremy Scholz (co-founder). Investors include Fidelity Investments (2021 lead), Obvious Ventures, Capricorn Investment Group and Vast Ventures; SETT (Spain) is a joint-venture partner.
Startuprad.io relevance
Diamond Foundry is covered in Startuprad.io's Unicorn Atlas special on the 23-company list of unicorns founded by TUM alumni, which UnternehmerTUM's press office supplied to Startuprad.io in October 2026. The special checks each company's TUM link, its billion-dollar milestone and any documented UnternehmerTUM programme or investment.
Public source context
This profile is drawn from public sources including Diamond Foundry, Financial Times (via company page), Reuters, Forbes España and Startuprad.io coverage. Time-sensitive figures, including valuations and ownership, are reported with their dates and should be re-verified against primary sources before commercial use.
Startuprad.io coverage of Diamond Foundry
Diamond Foundry appears in the following Startuprad.io interviews, news and analysis.
Exclusive: The 23-Unicorn List UnternehmerTUM Gave Us — and Where Its Role Is on Record
Published: 26 October 2026
Last updated: 26 October 2026
Coverage type: Analysis
https://www.startuprad.io/post/exclusive-the-23-unicorn-list-unternehmertum-gave-us-and-where-its-role-is-on-record
About this record. This is the public Level 1 layer of Startuprad.io's entity intelligence architecture. Startuprad.io's deeper entity intelligence may include extended profiles, verified relationships, source trails, historical development, monitoring, news signals, custom entity sets, and analytical relationship mapping. These deeper layers are available through Startuprad.io's research, intelligence, and enterprise services.
Need deeper entity intelligence? Startuprad.io provides extended profiles, monitored entity sets, relationship analysis, source-backed research, and custom intelligence services for companies, investors, and institutions. → https://www.startuprad.io/become-a-partner
For deep-tech founders working on materials and chip supply chains, our members-only briefings follow industrial-policy funding and what it means for hardware start-ups.
▶ YouTube Membership: https://www.youtube.com/startupradio/join
✉️ Substack: https://startupradio.substack.com/subscribe
About Startuprad.io
Startuprad.io is a European B2B media, data and intelligence platform. It provides structured entity and ecosystem data, source-backed research, datasets and AI/training-data solutions, as well as strategic visibility and access to a professional European audience of founders, investors, executives and B2B decision-makers.
Organizations use Startuprad.io for intelligence and research, structured data and AI applications, executive and company positioning, and trusted B2B reach across Europe.
Canonical record: https://www.startuprad.io/entities/diamond-foundry