earth science

Grandreefite

Grandreefite 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 Grandreefite rather than just read about it. In short: Grandreefite is a rare secondary lead sulfate-fluoride mineral with a general chemical formula, Pb2SO4F2. It is named for the location in which it was discovered in 1989, the Grand Reef Mine in Graham County, Arizona.

Key takeaways

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

Reference excerpt

Grandreefite is a rare secondary lead sulfate-fluoride mineral with a general chemical formula, Pb2SO4F2. It is named for the location in which it was discovered in 1989, the Grand Reef Mine in Graham County, Arizona. Grandreefite is monoclinic, falling in the 2/m symmetry group. Crystallographically this means, grandreefite has three axes of unequal length, with two angles at 90° to one another and a third, obtuse angle. The 2/m symmetry group indicates a two-fold axis with a perpendicular mirror plane. Grandreefite was originally classified as an orthorhombic mineral but was determined monoclinic instead upon further analysis. Pseudograndreefite, one of three other newly discovered minerals in 1989 at the Grand Reef Mine site, has orthorhombic crystallography. Optically, grandreefite is an anisotropic mineral, meaning the velocity of light varies depending on the direction through which it is passing through the mineral. Its calculated relief, i.e. its relative difference in index of refraction compared to the surrounding medium's index of refraction, is 1.96–1.98; and its birefringence is .025. Grandreefite, while not a valuable mineral in terms of commercial use, is useful in the sense that it is a good indicator of the very specific environment in which it forms and therefore the same conditions required to produce minerals similar to it in structure, composition, etc. For example, its structure is very similar to that of lanthanide oxide sulfates and therefore may be used to help better describe them. The Grand Reef Mine is located near a large granitic intrusion. Grandreefite is usually found in the mine in isolated veins containing hydrothermal copper, silver, and lead minerals hosted in oxidized breccias.

References

Kampf, A.R. (1991) Grandreefite, Pb2SO4F2;Crystal Structure and relationship to the lanthanide oxide sulfates, Ln2O2SO4. American Mineralogist, 76, 278-282. Kampf, A.R., Dunn P.J., and Foord E.E. (1989) Grandreefite, pseudograndreefite, laurelite, and aravaipaite: Four new minerals from the Grand Reef Mine, Graham County, Arizona. American Mineralogist, 74, 927-933.

Worked examples

Example 1 — a first encounter with Grandreefite

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

In research: Grandreefite 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 Grandreefite 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: Grandreefite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lead minerals, Minerals in space group 15, Monoclinic minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Grandreefite 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Grandreefite” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Grandreefite in 20 minutes

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

Frequently asked questions

What is Grandreefite in simple terms?

Why does Grandreefite 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 Grandreefite?

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 Grandreefite.