earth science

Shandite

Shandite is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Shandite rather than just read about it. In short: Shandite is a sulfide mineral with chemical formula: Ni3Pb2S2. It was discovered in 1948 by the German mineralogist Paul Raumdohr who named it named after Scottish petrologist, Samuel James Shand (1882–1957).

Key takeaways

Shandite belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Shandite to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Shandite from memory before moving on to harder problems.

Reference excerpt

Shandite is a sulfide mineral with chemical formula: Ni3Pb2S2. It was discovered in 1948 by the German mineralogist Paul Raumdohr who named it named after Scottish petrologist, Samuel James Shand (1882–1957). Ramdohr characterized shandite by its metallic luster and a brass-yellow color. It has a specific gravity of 8.92, and a Mohs hardness value of 4. Shandite is commonly found as an inclusion in other minerals such as Heazelwoodite Ni3S2 or serpentine. Its crystal system is trigonal hexagonal scalenohedral with symbol 32/m. It belongs to the space group R3m. Shandite is an anisotropic mineral, which means it has different properties when being viewed from different directions. In cross-polarized light it appears as gray blue or yellow-brown colors. It also has very distinct relief, which means it stands out against its mounting medium and can be easily seen. It has an index of refraction of 1.54, which is the measure of the speed of light through the substance. In plane polarized light, shandite has a creamy white color and distinct pleochroism, which is the property that makes it appear to be different colors at different angles. It has strong birefringence, which is the decomposition of light into two rays, and appears dark blue and gray. In subsequent decades several compounds with shandite type structure were synthesized by several chemists. The group of compounds M3A2Ch2 with shandite type crystal structures was subsequently called "shandites". They include Co3Sn2S2 = Sn2Co3S2 = Co3/2SnS that became famous in recent years as layered half metal ferromagnet and topological semi metal including kagome layers of cobalt atoms.

References

Paul Ramdohr: Über das Vorkommen von Heazlewoodit Ni3S2 und über ein neues ihn begleitendes Mineral: Shandit Ni3Pb2S2. Sitzungsberichte der Deutsch. Akad. d. Wiss. Berlin, Math-nat. Klasse. Band 6, 1948, pp. 1–30. Richard Weihrich, Rainer Pöttgen, Florian Pielnhofer: From Laboratory Press to Spins with Giant Effects. Angewandte Chemie. Internat. Ed., Vol. 57, pp. 15642-15644, doi.org/10.1002/anie.201811456. Manfred Zabel, Sigrid Wandinger, Klaus-Jürgen Range: Ternäre Chalkogenide M3M2'X2 mit Shandit-Struktur. Zeitschrift für Naturforschung, volume 34b, 1979, pp. 238–241. R. Weihrich, I. Anusca: Half Antiperovskites III: crystallographic and electronic structure effects in Co-Shandites. Zeitschrift für Anorganische und Allgemeine Chemie. volume 632, 2006, pp. 1531, doi:10.1002/zaac.200500524. R. Weihrich, S. F. Matar, V. Eyert, F. Rau, M. Zabel, M. Andratschke, I. Anusca, T. Bernert: Structure, ordering, and bonding of half antiperovskites: PbNi3/2S and BiPd3/2S. Progress in Solid State Chemistry. volume 35, 2007, 309–327, doi:10.1016/j.progsolidstchem.2007.01.011 E. Liu, Y. Sun, N. Kumar, L. Muechler, A. Sun, L. Jiao, S.-Y. Yang, D. Liu, A. Liang, Q. Xu, J. Kroder, V. Sgß, H. Borrmann, C. Shekhar, Z.Wang, C. Xi, W. Wang, W. Schnelle, S.Wirth, Y. Chen, S. T. B. Goennenwein, C. Felser: Giant anomalous Hall effect in a ferromagnetic kagome-lattice semimetal. Nature Physics volume 14, 11, 2018, 1125–1131, doi:10.1038/s41567-018-0234-5. W. Schnelle, A. Leithe‐Jasper, H. Rosner, F. M. Schappacher, R. Pöttgen, F. Pielnhofer, R. Weihrich: Ferromagnetic ordering and half-metallic state of Sn2Co3S2 with the shandite-type structure. Phys. Rev. B, volume 88, 2013, 1444041-8, DOI:doi.org/10.1103/PhysRevB.88.144404(?!) Mohamed A. Kassem, Yoshikazu Tabata, Takeshi Waki, Hiroyuki Nakamura: Low-field anomalous magnetic phase in the kagome-lattice shandite. Physical Review B, volume 96, 2017, 014429.

Illustrations

Worked examples

Example 1 — a first encounter with Shandite

Start with the simplest possible case. Write down what Shandite claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Shandite before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Shandite ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Shandite

In research: Shandite appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Shandite in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Shandite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lead minerals, Minerals in space group 166, Nickel minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Shandite outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Shandite in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Shandite means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Shandite out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Shandite in simple terms?

Why does Shandite matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Shandite?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Shandite.