earth science

Metarauchite

Metarauchite 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 Metarauchite rather than just read about it. In short: Metarauchite is a member of the autunite group, found at the Jáchymov ore district (type locality), Czech Republic and in Schneeberg, Germany. The autunite group is a group of structured uranyl phosphates and arsenates; the other members of the group are autunite, bassetite, heinrichite, kahlerite, nováčekite-I, nováčekite-II, rauchite, sabugalite, saléeite, torbernite, uranocircite, uranospinite, and zeunerite.

Key takeaways

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

Reference excerpt

Metarauchite is a member of the autunite group, found at the Jáchymov ore district (type locality), Czech Republic and in Schneeberg, Germany. The autunite group is a group of structured uranyl phosphates and arsenates; the other members of the group are autunite, bassetite, heinrichite, kahlerite, nováčekite-I, nováčekite-II, rauchite, sabugalite, saléeite, torbernite, uranocircite, uranospinite, and zeunerite. The mineral is named after Czech mineral collector Luděk Rauch, who died in the Jáchymov mines during mineral prospecting.

Occurrence Metarauchite occurs as a secondary mineral in strongly oxidized polymetallic vein material. Metarauchite is found primarily in two localities, the northern part of the Jáchymov ore district, northwestern Bohemia, Czech Republic and the Heber mine, Neustädtel, Germany. It is commonly associated with metazeunerite, erythrite, and gypsum (Jáchymov) and Ni-bearing metanováčekite, metazeunerite, pharmacosiderite (Schneeberg). Both localities have a surface containing strongly altered aggregates of primary ore with relics of uraninite, arsenopyrite and nickelskutterudite and traces of native bismuth at the Schweitzer vein in the Eduard mine.

Physical properties Metarauchite exhibits yellow to light greenish-yellow crystals, up to 0.8 mm in size, these crystals are transparent to translucent and display vitreous to pearly luster. It exhibits a hardness of 2 on the Moh's Hardness Scale. Displays thick tabular crystals, with a prevalent pinacoid (011). Metarauchite is very brittle and shows perfect cleavage along the {011} plane. Metarauchite does not exhibit fluorescence either in short- and long-wavelength ultraviolet radiation. The density of metarauchite is not easily measured because of the relatively small size of most of its crystals; hence only the calculated density from the unit cell parameters and empirical formula was obtained, giving the value 3.81 g/cm3 .

Optical properties Metarachite is biaxial negative, it exhibits its 2V is calculated at 52°. Metarauchite is non-pleochroic and displays no observable dispersion and a Gladstone-Dale index of 0.03.

Chemical properties Metarauchite is a Ni- and As-dominant member of the group of hydrated uranyl arsenates and phosphates with the autunite-type sheet containing divalent cations in their inter-layer. It is only isostructural with synthetic metakirchheimerite. Metarauchite displays prominent substitution for Mg with Co, but magnesium is more commonly substituted with Ni in species found at the Schneeberg locality. The empirical formula for metarauchite is (Ni00.82Co0.12Mg0.02)Σ0.96(UO2)2.01[(AsO4)1.88(PO4)0.03(SiO4)0.02]Σ1.93•8.21H2O (on the basis of 20 O,OH atoms). Simplified, the formula is Ni(UO2)2(AsO2)2•8H2O.

Chemical composition (Jáchymov)

Chemical composition (Schneeberg)

Crystallography Metarauchite is in the triclinic crystal system, with a space group of P1 and is classed as a pinacoidal. The cell parameters are a = 7.194(2) Å, b = 9.759(5) Å, c = 13.231(7) Å, α = 75.53(3)°, β = 84.01(3)°, γ = 81.59(3)°, which shows an a:b:c ratio of 0.737:1:1.356. The unit cell volume is 887.53 Å3 (Calculated from Unit Cell). Metarauchite crystals show characteristic multiply twinned along {011}.

Powder X-ray diffraction

Illustrations

Worked examples

Example 1 — a first encounter with Metarauchite

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

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

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

Frequently asked questions

What is Metarauchite in simple terms?

Why does Metarauchite 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 Metarauchite?

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 Metarauchite.