Hematite certified reference material: HMIE-Nano-Pellet

Hematite Mediterranean Italy Elba-Nano-Pellet (HMIE-NP) is our next certified Nano-Pellet from iron ore, which myStandards produced following the provisions of ISO 17034. Here you will learn about hematite and why we chose it to be one of our certified reference materials.

Properties of hematite and its usefulness as a certified reference material

Hematite is the main iron ore mineral with the chemical formula Fe₂O₃. The colour of naturally occurring hematite ranges from black to grey to brown-red. It has a density of 4.9 -5.3 g/cm³ and a Mohs hardness of 5.5 – 6.5. Even though hematite appears shiny black, its streak colour is blood red. That is why it used to be called bloodstone.

As with magnetite, the chemical composition or the distribution of the chemical elements in hematite provides information about its formation. In addition, it is possible to chronologically classify the formation of hematite through the decay of uranium within the hematite, a suitable mineral geochronometer.

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), for example, is suitable for analysing the chemical composition of hematite. In order for such analyses to give accurate results and thus also the correct conclusions, the analytical instruments must be calibrated with a material that is as similar as possible and has a known chemical composition. Our HMIE-NP is perfectly suited for this purpose. It consists of pure hematite, without binding agents, is matrix-matched and well characterised.

From hematite crystals to Nano-Pellets as reference material

As always, we followed our established procedure for certifying reference materials. All these steps were performed meticulously following ISO 17034 and are mandatory under this standard in order to designate a material or the values attributed to it as certified. In this way, we achieve a consistently high quality. An example of our data evaluation and the certification report with further information can be found on the HMIE-NP product page.

To give a brief overview of how we fully characterized our batches and how the values and uncertainties of HMIE-NP were obtained, the main steps of the process are also summarised here.

In the first step after planning, 500 g of crushed haematite (particle size 5-40 µm) were purchased from a mineral dealer and the identity of the material was confirmed by X-ray diffraction.
Next, the powder was prepared by our team through wet grinding, freeze drying and homogenisation in our production laboratory. To divide the powder, it was processed with a rotary sample splitter, resulting in a total of 37 batches in glass vials, 14 of which were used for characterisation. For storage, the vials were vacuum sealed with silica gel and stored in a desiccator. Chemical analyses were performed in two ISO 17025 accredited laboratories.

To check stability and homogeneity, these are measured on the Nano-Pellets. For this purpose, we produced a total of 64 Nano-Pellets from batch HMIE-NP-2021-10-B01 and analysed 10 % of them with LA-ICP-MS. To do so, we simulated delivery conditions and used a randomized measurement scheme adapted to a procedure of ASTM Guide E-826-14.

In a final step, we combined the results with the characterisation evaluation ending up with certified values including their combined and expanded uncertainties for a variety of analytes, all of which are listed in the certificate.

By the way, we are always interested in Feedback: In case you would like to see additional elements, isotopic ratios or further information which are not in the certificate or certification report feel free to contact us!

It is possible to press Nano-Pellets out of the remaining powders for other methods, e.g., LIBS or micro-XRF. These Nano-Pellets, because they lack a homogeneity- and stability test, will not be designated as certified, but are very well characterised for their chemical composition.

The Iron Ore Set

With the launch of our second certified microanalytical reference material from iron ore, we would also like to introduce our first Iron Ore Set. The Iron Ore Set includes the two mineral Nano-Pellets MAKR-NP (magnetite) and HMIE-NP (hematite) as well as the ore Nano-Pellet IF-G-NP (iron formation from Greenland). The Nano-Pellets come as 10 mm diameter packed in a one-inch round aluminium mount. The mount is CNC machined from aircraft grade aluminium and coated with Diamond Like Carbon (DLC). It is ideal for laser ablation (LA-ICP-MS) and simplifies handling and storage.

HMIE-NP is the third certified reference material from the mineral category and our second iron ore. More certified materials from the mineral category and iron ores will follow in the next few months, as well more Mineral Sets. Stay tuned!

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