Global tech stocks were rattled Tuesday by suggestions that China may move to ban the export of so-called rare earth elements, a group of metals and alloys that are integral to the sector's supply chain, as trade tensions between Washington and Beijing continue to escalate.

China controls more than 80% of the world's rare earth element market, despite sitting only just over a third of global reserves, thanks in part to a decades-long commitment to an expensive -- and environmentally damaging --  production process.

"Will rare earths become a counter weapon for China to hit back against the pressure the United States has put on for no reason at all? The answer is no mystery," an editorial in the People's Daily newspaper asked Wednesday. "Undoubtedly, the U.S. side wants to use the products made by China's exported rare earths to counter and suppress China's development. The Chinese people will never accept this."

European chipmakers with links to the smartphone supply chain, including Apple Inc. (AAPL - Get Report) supplies Dialog Semiconductor (DLGNF) and AMS AG (AMSSY) , were notably lower at the start of trading, falling 1.5% and 5.3% respectively, while larger semiconductor stocks such as ASML (ASML - Get Report) and STMicroelectronics (STM - Get Report) were seen 1.5% and 2.5% lower in Amsterdam and Milan.

Apple shares were marked 1.25% lower in pre-market trading in New York, indicating an opening bell price of $176.00 each, while chipmakers Micron Technologies (MU - Get Report) and Nvidia Corp. (NVDA - Get Report)  and Advanced Micro Devices (AMD - Get Report) were seen 1.7% and 1.3% and 1.1% lower respectively 

The rare earth card: China's reserves account for roughly 30% of the world's total, and the country produces more than 80% of the world's supply. 80% of the US' rare-earths imports between 2014 and 2017 are from China. pic.twitter.com/7rzoQ7QVd1

- Global Times (@globaltimesnews) May 29, 2019

The rare earth group, a collection of seventeen elements, are found in everything from flat screen televisions to smartphone batteries to military satellites and while they're not prohibitively expensive -- the U.S. imported around $160 million worth last year -- they are both difficult to recycle and impossible to replicate.

Furthermore, the U.S. has only one functioning site from which it can produce these crucial tech elements -- the Mountain Pass mine near San Bernardino, California -- and even it is forced to export what it pulls from the ground to China in order to have it refined for industrial use.

In fact, while China slaps a 25% tariff on imported rare earth elements, the U.S. has exempted them from the list of $300 billion worth of goods currently being studied by the Treasury Department for similar levies, given that the U.S. relies on China for around 80% of its rare earth finished products. 

China's first hint at leveraging its rare earth advantage came earlier this month, when President Xi Jinping visited a production site in the city of Ganzhou with his top trade negotiator, Vice Premier Liu He. 

Previous attempts by China to ban rare earth exports had some impact, with prices rising nearly 40% in the wake of a 2010 dispute between Beijing and Tokyo, but were ultimately stymied by a 2015 World Trade Organization ruling that criticized Chinese officials.

However, with Huawei Technologies now blacklisted from doing business with U.S. firms and Federal agencies, and the Trump administration actively undermining the WTO with bilateral tariffs on many of its allies, China could feel emboldened enough to use a similar 'national security' justification and reimpose an export ban.