The quartz mines in Spruce Pine, North Carolina, are owned and operated by two foreign-controlled companies: Sibelco, a privately held Belgian multinational headquartered in Antwerp, and The Quartz Corp, a joint venture between the French industrial minerals group Imerys and the Norwegian family-owned firm Norsk Mineral. Between them, these two operators account for an estimated 70 to 90 percent of the world’s high-purity quartz supply, drawn from pegmatite formations in Mitchell County that no other known deposit on Earth matches for purity.
Sibelco
Sibelco is the larger operator in the district. It is privately held and family-controlled, so it does not file the quarterly earnings reports or shareholder disclosures a public company would. Its presence in Mitchell County traces back to Unimin Corporation, which held extensive mining permits and processing infrastructure in the area for decades. Unimin was absorbed into Sibelco’s global operations, and when the parent company restructured its North American holdings around 2017 and 2018, the high-purity quartz business was specifically kept under Sibelco rather than spun off with other mineral assets.1U.S. Securities and Exchange Commission. SEC Filing – Unimin HPQ Business Retention
The company runs multiple extraction sites and processing facilities around Spruce Pine, taking raw pegmatite rock and refining it into the ultra-pure quartz sand that semiconductor and solar manufacturers depend on. An S&P Global credit analysis notes that Sibelco’s Spruce Pine operations benefit from strong demand tied to solar photovoltaic and semiconductor production, especially from Asian customers, with revenue visibility supported by long-term supply contracts.2S&P Global Ratings. Research Update: Minerals Producer Sibelco BBB- Rating Affirmed On Solid Operating Performance; Outlook Stable Because the company is private, outside visibility into its finances, production volumes, and expansion plans is limited to what it chooses to disclose.
The Quartz Corp
The second operator, The Quartz Corp, is a joint venture of two European parents. Imerys is a French industrial minerals company listed on Euronext Paris. Norsk Mineral AS is a privately held family firm based in Molde, Norway, with roots in mineral extraction going back to 1948 across three generations of family ownership.3Norsk Mineral. About Us4Norsk Mineral. The Quartz Corp
The Quartz Corp operates its own quarries and processing facilities in the Spruce Pine district, separate from Sibelco’s. Its production is aimed at semiconductor and solar customers who need the highest-purity quartz available. The ownership split between Imerys and Norsk Mineral is widely reported as 50/50, though neither parent’s public filings confirm the precise percentages. Both partners share operational oversight and financial responsibility for the venture’s assets in North Carolina.
Why Only Two Owners Matters
The U.S. Geological Survey confirms that only two companies produced high-purity quartz in the United States as of 2025, and both operate around Spruce Pine.5U.S. Geological Survey. Mineral Commodity Summaries 2026 – Quartz That concentration — a global supply chain running through two corporate entities in a single Appalachian valley — is why ownership here is treated as a strategic question rather than a corporate one.
The material coming out of these mines is not interchangeable with ordinary silica sand. It is used to make the quartz crucibles that hold molten silicon during semiconductor wafer and solar cell production, an application almost nothing else can perform. The U.S. Department of the Interior added silicon to its official list of critical minerals in 2025,6U.S. Geological Survey. Interior Department Releases Final 2025 List of Critical Minerals and the Department of Energy had already designated silicon as a critical material for energy under the Energy Act of 2020, citing both its role in solar cells and batteries and the risk of supply chain disruption.7Department of Energy. What Are Critical Minerals and Materials
Hurricane Helene made the risk concrete. When the storm hit western North Carolina in late September 2024, both Sibelco and The Quartz Corp shut down ahead of the flooding. Sibelco later reported only minor damage to its facilities and announced it had restarted production and customer shipments.8Sibelco. Sibelco Restarts Production and Customer Shipments at Spruce Pine Following Hurricane Helene USGS figures still show the impact: U.S. high-purity quartz sales fell from roughly 200,000 metric tons in both 2023 and 2024 to an estimated 100,000 metric tons in 2025.5U.S. Geological Survey. Mineral Commodity Summaries 2026 – Quartz Major silicon wafer manufacturers reportedly held three to eight months of stockpiles, which cushioned the shock while operations recovered.
How Mineral Ownership Works in the District
Spruce Pine is not one contiguous mine owned outright by either company. It is a patchwork of privately owned parcels, severed mineral interests, and corporate leases spread across the mountains. North Carolina law allows mineral rights to be separated from the surface estate through a deed or reservation, creating a split estate in which the mineral owner can drill, mine, explore, and remove subsurface resources even when someone else owns the surface above.9North Carolina General Assembly. North Carolina Code 47E-4.1
Subsurface mineral interests are treated as real property under state law and are subject to the same ad valorem property taxes as land and buildings.10North Carolina General Assembly. North Carolina Code 1-42.9 – Ancient Mineral Claims Extinguished In practice, Sibelco and The Quartz Corp typically secure long-term leases from the private landowners who hold the mineral rights rather than buying the land itself. Those leases and conveyances must be recorded with the county Register of Deeds to be enforceable against third parties; under North Carolina’s recording statute, an unrecorded instrument is not valid against later purchasers or creditors who had no notice of it.11North Carolina General Assembly. North Carolina Code 47-18 – Conveyances, Contracts to Convey, Options, and Leases of Land That recording requirement is where ownership disputes most often arise, when a landowner sells or leases mineral rights but fails to record the transaction promptly and competing claims result.
So the short answer to who owns the Spruce Pine quartz mines is two companies, both foreign, both operating under state and federal mining regulation. The longer answer is that the ground itself is a mosaic of leased mineral rights, and the two operators sit at the top of a supply chain the federal government now formally recognizes as critical.