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The Market is Waking Up to Halloysite

Updated: Apr 13, 2022

✦ Noel Ong, CEO of Samso clears the air on halloysite - an emerging material with game-changing green potential.

Halloysite is the lesser-known cousin of the common kaolin, and is potentially stealing the spotlight with its use in specialised green technologies and biomedical applications.

South Australia is positioned to be the biggest Halloysite mineral resource in the world. This is James Marsh's take on this new up-and-coming mineral. In fact, it was when Andromeda Metals Limited (ASX: ADN) first made news of their deposit in South Australia that the mineral resources investing community in the Australian Stock Exchange (ASX) first sat up and took notice of halloysite.

The humble halloysite has always been used as an alternative raw material to kaolinite for ceramics. Since 2005, halloysite has started to make a few heads turn. And today, we are looking at an exponential increase in research aimed at Halloysite Nanotubes (HNTs).

So for now, we have Andromeda Metals Limited keenly interested in halloysite, and just one other company, Suvo Strategic Minerals Limited (ASX: SUV), that is promoting the same story.

Halloysite is a unique mineral, so there is still a lack of information and clear understanding about this mineral.

What is Halloysite?

Basically, it is a unique form of kaolin. Kaolin is an industrial clay, sometimes known as 'china clay' and halloysite is part of the same subgroup of clay minerals as kaolinite.

Everything you want to know about Halloysite
Everything you want to know about Halloysite

It is a relatively rare mineral, and yet it is experiencing a sustained increase in demand due to its extensive applications in new age industries. That is why it is making the heads of global investors turn. Call it an emerging material or what you will, there is an interesting story to dig up here with halloysite.

For the hardcore geologists among us, halloysite is a 1:1 dioctahedral clay mineral that has been studied widely for applications in nanotechnology and as a mineral exploration guide for recognising regolith-hosted heavy rare earth element (HREE) deposits. [1]

Halloysite structure
Figure 1: (a) Straight, regular halloysite microtubles from Camel Lake. (b) Halloysite crystal morphology and atomic structure. (Photo 414524) [2]

According to [2], halloysite is a relatively common mineral that often crystallises together with kaolinite; the two polymorphs of kaolin are not easily separated. Deposits suitable for commercial development are, however, comparatively rare and occur either as relatively pure masses of halloysite (e.g. Dragon Mine, Utah; Camel Lake) or as large, lower-grade sources from which halloysite can be readily separated (e.g. Matauri Bay deposits, New Zealand).

Geological setting of halloysite deposits formed by acid groundwater at the Camel Lake site, near Maralinga, South Australia.
Figure 2: Geological setting of halloysite deposits formed by acid groundwater at the Camel Lake site, near Maralinga, South Australia.[2]

What is Halloysite used for?

Halloysite is becoming a big favourite in the medical field for biomedical applications. This includes uses for drug delivery, gene delivery, tissue engineering, cancer and stem cells isolation and bioimaging. (Ref: Proactive Investors)

There are new patents waiting to be approved, which means exposing the material to lucrative and exciting new markets including batteries, super capacitors, and cancer therapeutics.

Once investors have gained an understanding of the applications of halloysite in fast growing high-tech products, the natural next step is to see them flocking to stocks that provide exposure to the mineral. 

Andromeda Rising

Pure halloysite is currently priced at $5000 a ton, so there is a rush to find more of it.

Andromeda Metals Limited is drilling their Great White deposit which they continue to test and define the product of its ultra-bright halloysite-kaolin resource. Andromeda's Great White Deposit is essentially a high-quality, halloysite-kaolin resource located in South Australia. It has a 75% stake in the project and the other 25% if held by its joint venture partner Minotaur Exploration Ltd (ASX:MEP). For Andromeda, the high purity of their Great White material makes it a premium feedstock for the production of high purity alumina (HPA) which is used to make electronics, watch faces, smartphone components, and also a key ingredient for lithium batteries.

WIth that in mind, it's not surprising Andromeda is seeing its shares taking a positive turn.

This isn't exactly new news, as Noel had a coffee chat with James E Marsh from Andromeda Metals Limited in early 2021 and they were already talking then about how the company's vast resource of halloysite was going to make them a high quality kaolin miner then, and that nanotechnology could make them an even bigger company in the near future.

Noel and Mr. Marsh talked then about the downstream part of the company's story which is the unique part of the whole halloysite story. It is, in fact, the emerging part of the Kaolin-Kaolinite-Halloysite sector.

The number of scientific papers written with each year up to 2015 according to the appearance of (a) halloysite (diamonds) or (b) halloysite nanotubes (HNTs) in the Article Title, Abstract or Keywords (both sourced from Scopus© database) and (c) numbers of patents filed per year with halloysite in Article Title or Abstract (source Espacenet)
Figure 7: The number of scientific papers written with each year up to 2015 according to the appearance of (a) halloysite (diamonds) or (b) halloysite nanotubes (HNTs) in the Article Title, Abstract or Keywords (both sourced from Scopus© database) and (c) numbers of patents filed per year with halloysite in Article Title or Abstract (source Espacenet) [10]

The chart in Figure 7 is a great way of showing the influx of research in the halloysite sector. According to Mr. Marsh, there have been thousands of papers that written about this subject and there is a myriad of potential downstream products.

The halloysite message is still causing a lot of confusion in the market because of a lack of understanding of the downstream process and the myriad of potential products.

Grading Kaolin - Halloysite

How does one determine the quality of this material?

The way industrial clays are considered to have technical and economic qualities is solved by the process of categorisation. In the market, we hear of the term "white brightness" to classify the quality of halloysites.

Noel points to an article by Harvey and Keeling 2001 [7], showing four categories to grade the material.

Category 1: clays of high quality requiring major capital investment to supply large tonnage, international markets. Produced in Georgia (USA), Conrnwall (UK) and the Amazon Basin in Brazil.

Category 2: unique specialty clays for which advanced technologies are required to produce small tonnages for niche markets. Clay deposits in this category are typically of high purity and are found in somewhat uncommon geological settings. Minerals such as Hectorite and Bentonite are common types within this category.

Category 3: moderate quality clays requiring relatively low technologies, to supply predominantly local markets.

Category 4: clays of low quality requiring little or no processing.

Harvey and Keeling 2001 concluded by noting that Categories 1 and 2 clay projects are of a higher quality which require extended development times (from green-field to investment decisions) and significant pre-development capital investment.

On the other hand, the development of Categories 3 and 4 clays requires shorter times and lower levels of capital investment.

According to the article, Category 2 is where halloysite sits. Interestingly, the article mentions the Maauri and the Poochera deposits as type areas.

Location of Australian and New Zealand clay deposits.
Figure 6: Location of Australian and New Zealand clay deposits. [7]

There are no known hectorite in either Australia or New Zealand, although the geological setting of the North Island of New Zealand is in many ways similar to that of Nevada. Both Nevada and the central North Island of New Zealand have extensive areas of hydrothermally altered acid to basic volcanic rocks.

Interestingly, Noel's previous understanding of Australian clay deposits (Figure 6) was that they were all uneconomic. According to this paper [7], I was not far off the mark. The majority of the Australian clay deposits sits in Category 3 and 4, which are the lower value. These deposits are largely deemed uneconomical due to their logistics and location to market.

Mining Halloysite

The interesting thing is, in spite of that, there are still not that many people mining halloysite. Noel has done a bit of digging and his research shows there are really only two "world-class" locations - Dragon Mine in Tinitc, Utah (USA) and the Matauri Bay deposit in Northland, New Zealand.

1) Matauri Bay halloysite deposit, Northland, New Zealand.

According to [4], halloysite clay deposits have been mined and processed in the Keriker-Matauri bay area of Northland since the late 1940s. Since the mid 1970s, this has been the dominant continuous supplier of halloysite worldwide, averaging around 20,000 tonnes per annum (tpa).

The very pure halloysite clay dug at Northland’s Matauri Bay
Figure 3: The very pure halloysite clay dug at Northland’s Matauri Bay is exceptionally white and bright. It is exported for use in high-quality materials such as porcelain, bone china and technical ceramics. [7]

The operation was acquired in 2000 by Imerys from former owners New Zealand China Clays Ltd. Imerys Tableware NZ Ltd currently mines raw clay from open pit mines developed in the Matauri Bay and nearby Mahimahi rhyolite domes (Fig. 4). The raw clay contains around 50% halloysite, 50% silica minerals (quartz, cristobalite, tridymite, amorphous silica), and minor feldspar.

Geological map of the Kerikeri – Matauri Bay region of North Island New Zealand
Figure 4: Geological map of the Kerikeri – Matauri Bay region of North Island New Zealand (derived from Web Map (GNS Science, 2013) [5]) showing rhyolite domes and halloysite deposits, with sketch west-east section through the Matauri Bay halloysite deposit (after Brathwaite et al. (2012))

2) Dragon Mine [8]

Dragon mine is located in the Tintic District of north central Utah, some 60 miles southwest of Salt Lake City. The geology and details of alteration and mineralization at the Dragon mine are well described by several authors and the references can be found in [8]. The host rocks are Upper Cambrian Ajax Dolomite and Opex Formation with underlying Middle Cole Canyon Dolomite and Tintic Quartzite (Fig. 5).

There are two main clay bodies at the Dragon mine – West and East as shown in Fig. 5. Dragon was originally an iron ore mine and subsequent mining of halloysite was mainly from underground during 1947– 1976 with 1.35 million tons mined by Filtrol.

Geological section, approximately west–east, through the Dragon mine, Tintic mining district, Utah, showing the distribution of halloysite ore zones – redrawn from Kildale & Thomas (1957) and Morris (1985).
Figure 5: Geological section, approximately west–east, through the Dragon mine, Tintic mining district, Utah, showing the distribution of halloysite ore zones – redrawn from Kildale & Thomas (1957) and Morris (1985).

Halloysite was extracted using a square-set method (5.2 × 6.0 × 7.8 ft) and hand-drills, and it was transported to the surface via a shaft and then loaded onto a lorry, which delivered raw clay to the Filtrol plant in Salt Lake City for processing into a fluid cracking catalyst

(FCC) for the petroleum industry.

Other players

Wilson and Keeling 2016 [8] has Table 1 below which shows some of the halloysite sites around the world. Their work is pretty good in giving an idea of what is around. However, there have been several new players since Suvo Minerals identified halloysite on their Pittong Operations as well.

Some halloysite and mixed halloysite-clay deposits
Table 1: Some halloysite and mixed halloysite-clay deposits.[8]

There is a report in 2021 of a pegmatite in Brazil which has tubular halloysite and HREE (Heavy Rare Earth Elements), so discoveries are being made. As halloysite is chemically and physically different from normal kaolin-kaolinite, the identification of halloysite will happen more commonly. However, as you see how the categorisation/grading of these "clays" become clearer, the economic implication will cause many halloysite deposits uneconomical and hence, not important.

What's to Come for Halloysite

Halloysite is a space that is still evolving. Noel has spoken often about the emerging new "Industrial Revolution" (Ref: ( Expectations for the Mineral Resource Industry in 2022 - Green Energy and No Emission.) This new evolution is going to drive more need for the humble kaolin.

We wait in anticipation of what the next chapters are going to be like for players like Andromeda Metals Limited and Suvo Strategic Minerals. At the moment there are many products which are at a pilot stage, like Andromeda, but the success or lack of is unknown. Science shows that through a step process of test and pilot plants, this normally ends well but there is no ´sure thing´ concept here.

Andromeda has been the most active in promoting their vertical integration business model and the Andromeda website is a good place to get updates on information on the downstream products.

Some present and future uses and applications for halloysite.
Table 2: Some present and future uses and applications for halloysite. [8].

The way Andromeda has separated their products is interesting. Following the categorization observed in the paper by [7], it could be fitted as follows:

  • Kaolin (Category 3 and 4),

  • Halloysite Kaolin (Category 2 and 3)

  • High Purity Alumina (Category 1 and 2)

Suvo Strategic Minerals is continuing to develop their Pittong operations and recently announced some upgrade in their Kaolin grades - Further High Grade Halloysite at Trawalla, Grades Up to 32.4% - which will be good for the company. However, Noel thinks that if you can get simple kaolin to the market, that is a great achievement by itself.

The Kaolin space is so active now that having an operation like Pittong is some of the advantage that Suvo has over their competitors. Like all mineral projects, it is better to have an operation that is up and running than just building castles in the air talking about it.



  1. Victor Matheus Joaquim Salgado-Campos; Luiz Carlos Bertolino; Francisco José da Silva; Julio Cezar Mendes; Reiner Neumann, 2021, Mineralogy and chemistry of a new halloysite deposit from the Rio de Janeiro pegmatite province, south-eastern Brazil, Clay Minerals (2021) 56 (1): 1–15

  2. John L Keeling and Pooria Pasbakhsh, Halloysite Mineral Nanotubes – geology, properties and applied research. MESA Journal 77 Issue 2 – 2015

  3. Keeling JL 2015. The mineralogy, geology and occurrences of Halloysite. In P Pasbakhsh and GJ Churchman eds, Natural Mineral Nanotubes: Properties and Applications. Apple Academic Press Inc., New Jersey, pp. 96–112.

  4. Brathwaite, R.L.; Christie, A.B.; Faure, K.; Townsend, M.G.; Terlesk, S. Origin of the Matauri Bay halloysite deposit, Northland, New Zealand. Mineralium Deposita 2012, 47, 897-910.

  5. GNS Science. New Zealand Geology Web Map. (accessed June 12, 2013)


  7. Harvey, Colin C and Keeling, John, 2002 Categorization of industrial clays of Australia and New Zealand. Applied Clay Science 20, pp243-253.

  8. Wilson, Ian and Keeling, John. 2016. Global occurrence, geology and characteristics of tubular halloysite deposits. Clay Minerals, Vol 51, pp 309-324.

  9. Kildale M.B. & Thomas R.C. (1957) Geology of the halloysite deposit at the Dragon Mine. Pp. 94–96 in: Geology of the East Tintic Mountains and Ore Deposits of the Tintic Mining Districts (D.R. Cook, editor). Guidebook to the Geology of Utah, 12, Utah Geological Society, USA.

  10. Churchman, G. Jock, Pasbakhsh Pooria, and Hillier, Stephen. 2016. The Rise and Rise of Halloysite. Clay Minerals, 51, pp303-308.



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Brilliant-Online had repurposed Noel's article on Halloysite.

Noel Ong, CEO of Samso tells compelling stories by engaging business leaders to reveal insights beneficial to the investment community.

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