earth science

Lemanskiite

Lemanskiite 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 Lemanskiite rather than just read about it. In short: Lemanskiite is a mineral that was first discovered in a mine at Abundancia mine, El Guanaco mining district, Chile, with the ideal formula of NaCaCu5(AsO4)4Cl·3H2O. Originally, this mineral was discovered as being dimorphus with lavendulan, but in 2018 it was revised to only have 3 water molecules.

Key takeaways

Lemanskiite 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 Lemanskiite to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lemanskiite from memory before moving on to harder problems.

Reference excerpt

Lemanskiite is a mineral that was first discovered in a mine at Abundancia mine, El Guanaco mining district, Chile, with the ideal formula of NaCaCu5(AsO4)4Cl·3H2O. Originally, this mineral was discovered as being dimorphus with lavendulan, but in 2018 it was revised to only have 3 water molecules. Lemanskiite typically occurs as rosette-shaped aggregates of thin lamellar or needle-shaped aggregates, such as lammerite. Lemanskiite is dark sky blue with a light blue streak, it is brittle with an excellent cleavage plane. It was found on a dumping site in the abandoned Abundancia mine, El Guanaco mining district, Region II, Antofagasta Province, Chile The new mineral has been named after Chester S. Lemanski, Jr. This mineral and name were then approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association.

Location, occurrence, and paragenesis The Abundancia gold mine, El Guanaco mining district, is located south of Cerro La Estrella. The quartz veins contain several sulfides, mostly enargite, and it is associated with coarse grains and crystals of dark green lammerite. Other associated minerals include green crystals of olivenite, gray crystals of mansfieldite, white grains of senarmontite, and with a mixture from the crandallite group. Its intergrowths indicate very acid conditions of origin, characteristics of epithermal deposits.

Physical properties Lemanskiite normally forms with a habit of very large nodules up to five centimeters long; it can also form with veins of quartz. Lemanskiite has two different types of occurrences, needle-shaped and rosette-shaped aggregates. The needle-shaped aggregates are very thin plate-like individual crystals with a length of 0.8 mm and have a thickness of 10 μm. The rosette-shaped aggregates are thin, lamellar, subparallel intergrowths with very thin individual domains. Lemanskiite comes in a dark sky blue color. The mineral has also been found to be translucent. Lemanskiite has a hardness of around 2.5 on the Mohs scale, and has a density of 3.78 g/cm3. It has excellent cleavage parallel to the largest face visible which is (001), has a brittle tenacity, has a light blue streak, and has a vitreous luster.

Optical properties Lemanskiite is uniaxial negative. The refractive indices ω = 1.749(2) and ε = 1.647(2), and It has high surface relief. It has strong pleochroism with a O value of dark green-blue and an E value of light blue-green (light turquoise).

Chemical properties Lemanskiite is a hydrous copper, calcium, and sodium chlorarsenate. The idealized formula is NaCaCu5(AsO4)4Cl·3H2O. The empirical formula of this mineral, calculated on the basis of 20 O + Cl is Na0.98(Ca0.98Sr0.03)Σ1.01Cu5.07As3.97O15.97Cl1.03•3H2O. Lemanskiite is no longer a dimorph of lanendulan due to the lower H2O content, as it was discovered in 2018, to actually less hydrated.

Crystal structure Lemanskiite is a member of the lavendulan group, and has a crystal structure that is based on heteropolyhedral layers parallel to (100). The heteropolyherdal layer are represented as Cu2+-centered polyhedra and AsO4 tetrahedra. This new structural type being formed, shows clusters of four-edge shared copper fivefold polyhedra forming distorted tetragonal pyramids, with a chlorine being the shared apex. However, even though lemanskiite is a member of the lavendulan group, it differs in that the fourth vertex in each of the AsO4 is linked a copper-centered without a copper fivefold polyhedra cluster. Due to this, this copper site is instead a centered tetragonal pyramid with the oxygen atom of water molecule at a distant fifth apex CuO4(H2O).

Chemical composition

X-ray crystallography A single of lemanskiite, with excellent cleavage along the (001) plane, was examined with a XCalibur CCD diffractometer. Lemanskiite is in the monoclinic crystal system in the space group P21/m. The study of lemanskiite, performed at room temperature, produced the following data for a single unit cell of the crystal: a = 9.250(2) Å, b = 10.0058(10) Å, c = 10.0412(17) Å; β = 97.37°, V = 921.7(3) Å3. The powder X-ray diffraction data of lemanskiite was analyzed on a Rigaku R-AXIS RAPID II diffractometer utilizing CoKa radiation (λ = 1.79021 Å) in the Debye-Sherrer geometry (d = 127.4 mm). The collected data was integrated to account for several weak reflections in the data set. The final collected data of the two minerals in the powdered sample was 97.9% lemanskiite and 2.1% quartz.

Illustrations

Worked examples

Example 1 — a first encounter with Lemanskiite

Start with the simplest possible case. Write down what Lemanskiite 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 Lemanskiite 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 Lemanskiite 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 Lemanskiite

In research: Lemanskiite 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 Lemanskiite 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: Lemanskiite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Arsenate minerals, Calcium minerals, Chloride minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Lemanskiite 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 Lemanskiite in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lemanskiite 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 Lemanskiite out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lemanskiite in simple terms?

Why does Lemanskiite 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 Lemanskiite?

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 Lemanskiite.