earth science

Pinalite

Pinalite 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 Pinalite rather than just read about it. In short: Pinalite is a rare lead tungstate–chloride mineral with formula: Pb3WO5Cl2. Pinalite crystallizes in the orthorhombic crystal system.

Key takeaways

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

Reference excerpt

Pinalite is a rare lead tungstate–chloride mineral with formula: Pb3WO5Cl2. Pinalite crystallizes in the orthorhombic crystal system. The orthorhombic system is described as having three crystallographic axes of unequal lengths, normally referred to as c (the longest axis), b (the second longest axis), and a (the smallest axis). These axes all have corresponding angles of 90 degrees. Pinalite belongs to the biaxial optical class, and is negative. The main difference between biaxial and axial crystals is that biaxial crystals have two optic axes. Pinalite's structure is significant in that it is one of a kind. It is therefore important in seeing how the structures in new lead oxyhalides (containing square pyramids incorporated into sheets) are arranged. Its structure contains an extra oxygen, which therefore has a very small amount of free space and consequently protrudes into neighboring layers. The oxygen then pushes aside the chlorine atoms, leaving almost no room for the lead to occupy. This is of interest to geologists for it is such a rare occurrence of structure seen only in pinalite and its barium analog. Therefore, it could be of use to structuralists to see how this mineral was formed. Experiments have been done, using lead oxyhalides, to see the reason and sequence of events in which this mineral is executed.

Discovery and occurrence Pinalite was first discovered in 1989 in the St. Anthony deposit, Tiger, Mammoth District, Pinal Co., Arizona, US, and was named for the location county. Pinalite has otherwise only been seen in the Grand Reef mine, near Klondyke in the Santa Teresa Mountains in Graham County, Arizona, so is therefore found around orogenic activity.

References

Worked examples

Example 1 — a first encounter with Pinalite

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

In research: Pinalite 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 Pinalite 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: Pinalite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chloride minerals, Lead minerals, Minerals in space group 63, so understanding it makes those chapters shorter.
In everyday life: Look for Pinalite 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 Pinalite in 20 minutes

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

Frequently asked questions

What is Pinalite in simple terms?

Pinalite is a rare lead tungstate–chloride mineral with formula: Pb3WO5Cl2. Pinalite crystallizes in the orthorhombic crystal system.

Why does Pinalite 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 Pinalite?

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 Pinalite.