Continental is a Minneapolis supplier with a Denver outpost.

Continental Clay Company is registered in Minnesota as a business corporation filed on 16 March 1990 and in good standing, with Michael C. Swartout as its chief executive, the state’s register shows. The company calls itself “a family owned company.” It does not name a founder on its website, and we do not either.

It is easy to find. Its Minneapolis home, it says, is at the “SE corner of Interstate 35W and Stinson Blvd … near the University of Minnesota campus,” and it runs a second location in Denver, on East 47th Avenue; we could not confirm whether clay is mixed there or only sold. Its toll-free number spells the product — 800.432.CLAY. In Minneapolis, it says, “we have over 65,000 square feet dedicated to clay mixing, glaze production, research and development and … our retail store and gallery.” Factory, laboratory and shop, in other words, share one Minneapolis address.

The register also records several administrative dissolutions for late filings since 2015, each reversed within weeks — routine paperwork, not a change of ownership or control, which we mention only because the register shows it.

“The raw clay we use comes directly from the mines.”

Continental’s brand claim is about supply. “The raw clay we use comes directly from the mines,” it says. “Our talented crew … hand blend and bag over four million pounds of clay and glaze per year.” And it describes its sources broadly: “All of Continental Clay Company’s products are made from the industries most refined and processed clay mines … brought together at Continental Clay from origins through out North America and worldwide.”

It names a few. Its Grolleg Porcelain is “made with Grolleg kaolin from England,” and its Domestic Porcelain “with US kaolins and clays.” It sells slip clays under three historic names — Albany, Alberta and Sheffield; the last is also the name of this round’s Massachusetts clay maker, Sheffield Pottery, which says the original Albany Slip mine “closed in 1986.” It says it stocks “over 26 premium ready to use pottery clays along with providing hundreds of custom mixes,” from B Clay, a “Premium Porcelain-Stoneware blend,” and a Buff Stoneware it calls “One of our most popular clays used in schools,” to a Wood Fire Porcelain for cone 8 to 12. Between them sit a Dark Iron Stoneware that gives a “‘Reduction look’ in oxidation,” coarse red and white bodies, a soda clay, a raku body for cone 06 to 10 and a tableware stoneware — a range built for every kind of kiln a school or studio might own.

The supply chain shows on its pages. A notice asks customers to confirm prices and availability, its clay page says “PLEASE CALL AHEAD BEFORE COMING TO PICK-UP ANY CLAY,” and its own glazes and underglazes were marked temporarily unavailable when we checked. A clay house that buys directly from the mines is exposed to the mines’ schedules. It is not alone: Standard of Pennsylvania currently warns its customers that a supplier “has been mining the RedArt clay from a different seam,” so fired colours may vary. Supply notices like these are the visible edge of an invisible geology.

From the mines — which mines?

The US Geological Survey sketches the mines Continental describes. American clay output was about 26 million tonnes in 2025, from about 120 companies in 38 states; ball clay came to about 990,000 tonnes and kaolin to about 4.8 million. The USGS’s 2019 yearbook says ball clay was produced in five states, led by Tennessee, and kaolin in six, with “Georgia account[ing] for 92% of the U.S. kaolin production.” Continental names England for its Grolleg — a china clay from Cornwall — and the United States for its domestic kaolins; it does not name the mines, and we do not guess. In Georgia, the same yearbook adds, paper coating took 35 per cent of domestic kaolin sales in 2019 and ceramics 23 per cent. American ball-clay output has drifted down, from about 1.08 million tonnes in 2021 to an estimated 990,000 in 2025.

Most of what those mines produce never reaches a potter. The USGS puts ball clay’s leading use at floor and wall tile, 53 per cent, and says only 20 per cent of kaolin went to ceramics in 2025; about 1.6 million tonnes of kaolin were exported, mainly for paper. At the mine, ball clay was worth about $47 a tonne and kaolin $170. Four million pounds a year — about 1,800 tonnes — makes Continental a substantial studio supplier but a small customer of the mining industry. Its value lies in the blending, which the British Geological Survey says “reduces the natural variability of the clays.” Even the name of the raw material is a relic of old practice: “ball clay,” a 1975 British dossier says, is “believed to be derived” from the clay once being cut in pits into cubes, or “balls,” of 15 to 17 kilograms.

Continental is also direct about health. “The fundamental health concern in the ceramics industry is silicosis,” its safety page begins. It says all its prepared moist clays are “AP NON TOXIC” and that “Over 98% of Continental Clay glazes and all of Continental Clay underglazes are lead-free” — its statements, which we report as such.

A phone number that spells the product.

Continental’s identity is functional rather than decorative: a plain website, a page title that lists what it sells — pottery supplies, equipment, wheels, kilns — and a phone number that spells CLAY. We found no tagline. For a supply house, the brand is the stock, the blending and the counter where potters pick up their bags.

For a design guide, Continental shows how a business can make its supply chain its claim without naming every link. “Directly from the mines” is a promise about freshness and control; “four million pounds” is a promise about scale. Both are checkable in a way that a slogan is not.

For this guide we use a Mississippi blue and a pale slate with a plain sans. These are an unofficial interpretation, not Continental’s colours, and nothing of its logo is reproduced.

Keep Continental Clay’s identity on hand — save it to a board in the Made Good inspiration library.