Almost all of these minerals come from China. Lakaz’s job is to provide the world with another source, just in case the trade war is out of control and China will cut off supply.

But now, she is very difficult to do. Her company, Lynas Corporation, can only provide a small portion of China's minerals, which are called rare earths. Not only that, but the source is also unstable. The work was complicated and expensive, and Linus was on the verge of collapse.

On Tuesday, the Trump administration stepped up its trade war with China and threatened to add taxes to an additional $200 billion in Chinese products. In addition to tax increases, China can use other forms of retaliation, which can refuse to buy American products, such as Boeing's aircraft. It may strengthen the regulation of US companies doing business in mainland China. It may also threaten to sell its huge US Treasury bond portfolio, which will disrupt the bond market.

There is also a more strategic weapon that China can use to cut off global supply chains. China is a major supplier of a range of common but important materials and components that are needed to maintain operations around the world. These include arsenic in semiconductors, cadmium in rechargeable batteries, tungsten in light bulbs and other heating elements.

It also includes rare earths. Trade wars put these minerals in conflict, and China may counterattack by cutting off supplies to US companies. Rare earths have been involved in this conflict. On Tuesday, the Trump administration issued a long list of Chinese-made goods that it hopes to tax.

China has used its control of rare earths to achieve its goals. In 2010, due to territorial disputes, it stopped exporting to Japan for two months. Speculators hoarded rare earth mines, causing prices to soar.

Ryan Castilloux, founder of the research firm Adamas Intelligence, said: "There are loopholes in the Western supply chain."

Without rare earth, you can’t go on for a day. There are rare earths in mobile phones, TVs, hair dryers, and electric cars.

They are not rare and consist of 17 elements. However, as far as Linus is concerned, converting a single mineral into a useful material is very complicated and expensive.

Large-scale rare earth refining is carried out in only two places around the world: China and Linus's plant in Kuantan, Malaysia.

For Linus, China is the most direct challenge. Linus is now profitable, but Lakaz believes that the potential trade war between China and the United States is not so much an opportunity as a threat. The Chinese government can keep rare earths away from the market and deprive many US and European manufacturers of the mineral resources they need.

Linus can't make up for it all. According to Diamond Intelligence Research, last year, Linus only accounted for 12% of the world's rare earth output. Chinese companies account for more than 4/5.

Lakaz said: "If the comprehensive trade war begins, I can't believe that China does not use rare earth." If China wants to limit the supply of rare earths by taxing or stopping exports of rare earth products, "it can be done overnight."

In this case, companies will seek alternatives to rare earths. For example, Tesla Motors chose engines that did not require rare earths after the surge in rare earth prices in 2010. This will hurt Linus’s business.

The China Rare Earth Industry Association did not respond to requests for comment.

Even if the supply is not cut off, China will continue to maintain control of the rare earth market for a long time. Lakaz said that it also dominates the research and development of these minerals, making it an advantage in the future.

She said: "About 100 doctors in China are engaged in technology development in the field of rare earths. As far as I know, do you know how many such doctors are outside China?" She put a "0" shape with her fingers.

She said that for other countries, this means having to rely on China for a long time. "This didn't scare me, but it should scare policy makers.