Brimstone
Brimstone is a climate tech company in Oakland, United States, founded in 2019. It has raised $21.5M across 3 rounds, most recently a $21.0M Venture Round in August 2025.
Transforming Industry
- Headquarters
- Oakland, California
- Employees
- 51–200
- Founded
- 2019
- Business Model
- B2B
- Website
- brimstone.com
- Total Funding
- $21.5M
- Last Round
- $21.0M Venture RoundAug 2025
- Rounds
- 3
Totals include recorded grants and other qualifying funding, not just equity. What counts toward funding.
Indexed holds 3 funding rounds and 1 investor for this company. The full record is or through the API.
About
Brimstone is a deep tech company developing the Rock Refinery, a patented co-production process that refines calcium-bearing silicate rock into portland cement, supplementary cementitious materials (SCM), alumina, and other industrial materials. The process eliminates CO2 emissions tied to limestone calcination, which accounts for the majority of cement's carbon footprint, while delivering cost-competitive products at industrial scale.
Summary
It lists 51–200 employees. It has raised $21.5M in total across 3 rounds, most recently a $21.0M Venture Round in Aug 2025. Investors include Kajima Ventures.
Tech & App Stack
2 technologies & apps tracked
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Funding History
Aug 2025
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Funding: Grant through Venture Round. Amounts, valuations, and investors where available.
Investors
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