earth science

Roscoelite

Roscoelite 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 Roscoelite rather than just read about it. In short: Roscoelite is a green mineral from the mica group that contains vanadium. The chemical formula is K(V3+, Al, Mg)2AlSi3O10(OH)2.

Key takeaways

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

Reference excerpt

Roscoelite is a green mineral from the mica group that contains vanadium. The chemical formula is K(V3+, Al, Mg)2AlSi3O10(OH)2. Crystals of roscoelite take on the monoclinic form, and are from the 2/m point group. The appearance is semi transparent to translucent coloured olive brown to green brown. The lustre is pearly. The mineral shows pleochroism with X showing green-brown, and Y and Z axes showing olive-green colour. The mineral was named after Henry Enfield Roscoe who first produced vanadium metal.

Chemical properties Roscoelite is a muscovite with aluminium substituted with vanadium. Vanadium can also be substituted by magnesium, iron, or manganese.

Physical properties It is soft and the density is 2.93±0.01. The unit cell has dimensions

a = 526 pm b = 909 pm c = 1025 pm, with an angle between axes of β=101.0°. The tetrahedral cation-oxygen atom distance is 164.1 pm, The distance from the cation to the oxygen in the octahedral plan is 202 pm.

Formation Two kinds of mineral deposits contain roscoelite, either gold-silver-tellurium low temperature epithermal deposits where it occurs along with quartz, fluorite, pyrite and carbonates, or oxidized low temperature uranium-vanadium ores in sedimentary rocks, where it occurs with corvusite, hewettite, carnotite and tyuyamunite. Roecoelite is considered a gangue mineral of no value when found with gold. However it has also been used as a vanadium ore. In the Mt. Kare mine in New Guinea the mineral occurs with gold and is an important maker of gold deposits. The temperature of the geothermal fluid that deposited the roscoelite was from 127 to 167 °C (261 to 333 °F). The fluid contained a high level of salt and also contained carbon dioxide, methane, carbonyl sulfide and other minor amounts of rock forming elements.

Occurrence The mineral has been found in numerous places in US, Australia, Japan, Gabon, Fiji, New Guinea and Czech Republic. In the United States, it was the principal vanadium ore mineral at the mines at Placerville, Colorado. In Australia roscoelite has been found at Kalgoorlie, Radium Hill and the Kintore Open Cut at Broken Hill.

References

Illustrations

Worked examples

Example 1 — a first encounter with Roscoelite

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

In research: Roscoelite 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 Roscoelite 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: Roscoelite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dioctahedral mica group, Minerals in space group 12, Monoclinic minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Roscoelite 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 Roscoelite in 20 minutes

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

Frequently asked questions

What is Roscoelite in simple terms?

Roscoelite is a green mineral from the mica group that contains vanadium. The chemical formula is K(V3+, Al, Mg)2AlSi3O10(OH)2.

Why does Roscoelite 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 Roscoelite?

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 Roscoelite.