The same element, two different kinds of not knowing

Cobalt makes a reliable blue. In a glaze bucket it is a colorant with known firing behavior, a variable you can adjust, a material you can see the results of on a test tile. In a phone battery it is a cathode input, sealed inside a case, invisible to the person holding the device.

Both uses draw on the same mineral category. That shared category is the reason a craft audience has any business reading a supply-chain report about phones. It is also the reason to be careful about what that report does and does not say.

What is actually documented

Amnesty International and Afrewatch published a campaign report in 2016, updated in 2017, on cobalt mining in the Democratic Republic of the Congo. The page states that more than half the world’s cobalt comes from the DRC, that about one fifth of DRC cobalt is extracted by artisanal or informal miners, and that UNICEF estimated about 40,000 boys and girls work as artisanal miners in southern DRC, many of whom extract cobalt.

Those figures are from the retrieved source and carry its date. They are not current production statistics. They are the numbers the report used to establish scale.

The report describes a chain. Children and adult miners extract cobalt ore, then sell to traders. Amnesty and Afrewatch researchers followed the ore from artisanal mines to Musompo, the main trading market in Kolwezi. There, the report states, independent traders, most of them Chinese, bought ore without asking which mine it came from or how it had been mined.

From Musompo the ore moved to larger companies in the DRC that process and export it. At the center of that trade, according to the report, was Congo Dongfang Mining International (CDM), owned by China-based Zhejiang Huayou Cobalt Company Ltd. CDM smelted the ore in the DRC before exporting it to China. Huayou Cobalt then further smelted and sold processed cobalt to battery component manufacturers in China and South Korea. Those companies sold components to battery manufacturers, which sold on to consumer brands. The report names Apple, Dell, Huawei, Lenovo (Motorola), LG, Microsoft, Samsung, Sony, Vodafone, Daimler AG, Volkswagen, and BYD among those brands.

The harm, as reported

The report is specific about conditions. Children described working up to 12 hours a day, hauling loads of 20 to 40 kilograms for US$1–2 per day, often with nothing to eat all day. One 14-year-old told researchers he would spend 24 hours down in the tunnels. The report states that inhaling cobalt dust can cause hard metal lung disease, a potentially fatal condition, and that skin contact can cause dermatitis, a chronic rash. The children and other miners had neither masks nor gloves.

These are attributed findings from a named NGO report, not independent measurements. The methodology was researcher interviews and site visits, documented in the report itself. The report also notes that the DRC government admitted in August 2017 that children were working in cobalt mines and pledged to end child mining by 2025. Whether that pledge was met is not established by the retrieved source.

Where the ceramic glaze enters, and where it does not

Cobalt oxide and cobalt carbonate are common glaze colorants. That is craft chemistry, not a supply-chain claim. The retrieved source does not document ceramic-specific cobalt supply chains. It does not say that any particular bag of cobalt oxide, any studio, or any glaze recipe is connected to the mines it describes.

What the report documents is a general market condition: a mineral category that moves through opaque trading at the extraction stage and becomes more legible as it approaches the brand. Artisanal miners, traders, and smelters are named. Consumer-facing brands are the ones pressed to disclose.

Craft suppliers occupy a different position. They are often small. They may buy through distributors. They are rarely asked to publish smelter lists. That difference is not evidence of worse practice. It is evidence of a different accountability structure.

Two kinds of ignorance

There is not knowing because information is unavailable. There is not knowing because no one has asked.

The phone industry has been asked. After the Amnesty report, Apple published a list of all its cobalt smelters, and Sony published details of its cobalt supply chain for the first time. Those disclosures are documented in the report. They are not proof that child labor was eliminated. They are proof that the question was put and a public answer was required.

The craft supply chain has largely not been asked in the same way. A potter buying cobalt oxide from a distributor typically receives a chemical name, a grade, and a price. Country of origin may or may not appear on the label. The name of the mine or smelter almost certainly does not.

That is a gap in the record. It is not a verdict on the material.

What a potter can actually ask

The honest studio response is not a boycott claim. A potter cannot infer from the Amnesty report that a particular bag of cobalt oxide is connected to child labor. The report documents a market condition, not a batch-level traceability system.

What a potter can do is ask questions that distinguish between what a supplier knows and what a supplier has never been asked to find out. A practical framework, offered as a recommendation rather than a research finding:

• Ask for the country of origin of the cobalt in the batch. If the answer is a continent or a trading hub rather than a country, that is information about the supply chain’s legibility.
• Ask whether the supplier traces to specific mines or smelters, or whether they buy from a distributor who does. The distinction matters. “We buy cobalt” and “we know where this batch came from” are different statements.
• Ask whether the supplier has a due-diligence policy for cobalt sourcing. If they do not, ask whether they have been asked before.
• Ask what the material safety data sheet says about handling cobalt colorants in a studio. That is a separate question from mining exposure, and it has a documented answer in the SDS.

None of these questions will produce a clean chain of custody. They will produce a clearer picture of where the information stops.

The asymmetry worth carrying back to the bench

Phone brands were pressed to disclose smelters. Some did. Craft suppliers face far less scrutiny. That asymmetry is not about which material is more dangerous or which maker is more ethical. It is about how making is organized, priced, and remembered.

A blue glaze is a visible result. The supply chain behind it is mostly invisible. The phone in your pocket is the reverse: the supply chain has been documented and contested, while the cobalt inside is sealed away.

The question a potter carries back to the bench is not whether to use cobalt. It is what your supplier can tell you about origin, and what they cannot. The answer to that second part is the part that has not been asked enough.

FAQ

Does the Amnesty International report say that ceramic glazes use cobalt from the DRC artisanal mines it describes?

No. The report documents cobalt mining in the DRC and traces a chain to battery component manufacturers and consumer electronics brands. It does not document ceramic-specific supply chains or claim that any glaze supplier sources from the mines it describes.

Are the production figures in the report current?

The report was published in 2016 and updated in 2017. The figures it cites—more than half of world cobalt from the DRC, about one fifth from artisanal mines, about 40,000 child miners in southern DRC—are from that period. They should not be read as current 2026 statistics.

What is the difference between cobalt oxide and cobalt carbonate in a glaze?

Both are common cobalt colorants used in ceramic glazes. They differ in cobalt content and in how they are typically introduced into a glaze recipe. The retrieved source does not address ceramic chemistry, and this article does not make claims about firing behavior or substitution.

Can a potter trace a bag of cobalt oxide to a specific mine?

Not through the documentation cited here. The report describes a trading system at the extraction stage where ore was bought without asking which mine it came from. Whether any ceramic supplier has since established batch-level traceability is not established by the retrieved source.

What should a potter ask a supplier?

Country of origin, whether the supplier traces to specific mines or smelters, whether they have a due-diligence policy, and what the material safety data sheet says about handling. These questions are recommendations, not findings from the report.