earth science

Tyrrellite

Tyrrellite 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 Tyrrellite rather than just read about it. In short: Tyrrellite is a selenide mineral that has a chemical formula of Cu(Co,Ni)2Se4. It has been found in the Goldfields District in northern Saskatchewan, as well as in the Petrovice deposit, Czech Republic.

Key takeaways

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

Reference excerpt

Tyrrellite is a selenide mineral that has a chemical formula of Cu(Co,Ni)2Se4. It has been found in the Goldfields District in northern Saskatchewan, as well as in the Petrovice deposit, Czech Republic. It is named after the Canadian geologist Joseph Burr Tyrrell. Joseph Tyrrell was one of the first geologists from the Geological Survey of Canada to do research in the Goldfields District.

Crystallography Tyrrellite is isometric, meaning that crystallographically, it has three axes of equal length perpendicular to one another. It belongs to the space group, Fd3m. Because tyrrellite is isometric, it is also isotropic. Isotropic minerals are defined as follows: when light passes through an isometric mineral, the light moves in all directions with equal velocity. In contrast, for anisotropic minerals, the velocity of light passing through the mineral varies with crystallographic direction. Tyrrellite displays a light bronze color when viewed in plane polarized light. Because tyrrellite is isotropic, the light bronze color will remain constant as the mineral is rotated and viewed from different crystallographic angles. When viewed under cross polarized light, tyrrellite displays total extinction, a characteristic trait of isotropic minerals.

Discovery and occurrence It was first described in 1953 for an occurrence in the Goldfields District, Saskatchewan, while the second occurrence was reported in Petrovice deposit, Czech Republic. In general, tyrrellite is veined, embayed and replaced by umangite, a primary mineral of deposits in which tyrrellite is found. The relative scarcity and unique occurrences of tyrrellite can give geologists considerable insight into the circumstances under which the parent rock formed.

References

Illustrations

Worked examples

Example 1 — a first encounter with Tyrrellite

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

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

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

Frequently asked questions

What is Tyrrellite in simple terms?

Why does Tyrrellite 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 Tyrrellite?

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 Tyrrellite.