earth science

Tarbuttite

Tarbuttite 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 Tarbuttite rather than just read about it. In short: Tarbuttite is a rare phosphate mineral with formula Zn2(PO4)(OH). It was discovered in 1907 in what is now Zambia and named for Percy Coventry Tarbutt.

Key takeaways

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

Reference excerpt

Tarbuttite is a rare phosphate mineral with formula Zn2(PO4)(OH). It was discovered in 1907 in what is now Zambia and named for Percy Coventry Tarbutt.

Description and habit Tarbuttite is white, yellow, red, green, brown, or colorless; in transmitted light it is colorless. Traces of copper cause green coloring, while iron hydroxides cause the other colors. Colorless crystals tend to be transparent while colored specimens have varying degrees of transparency. The mineral occurs as equant to short prismatic crystals up to 2 cm (0.79 in), in sheaf-like or saddle-shaped aggregates, or as crusts. Individual crystals are commonly rounded and striated.

Structure Zinc ions are surrounded by oxygen in a nearly perfect trigonal bipyramid and phosphate groups are tetrahedral. The crystal structure consists of zig-zag chains of Zn1 polyhedra linked by phosphate groups and pairs of Zn2 polyhedra. In each unit cell are two formula units of Zn2(PO4)(OH).

History Tarbuttite was discovered in 1907 in Broken Hill mine, Northern Rhodesia, (now Kabwe, Zambia). The mineral was described from specimens in cellular limonite in the largest hill of the group, Kopje No. 2. In a cave discovered in Kopje No. 1 by boring a tunnel, tarbuttite was also found in association with hopeite as obscure crystals and crystals smaller than 1⁄16 mm (0.0025 in) and as an encrustation on some bones. Several specimens of the mineral were collected by Percy Coventry Tarbutt, a director of the Broken Hill Exploration Company. In 1907, the name tarbuttite was proposed by L.J. Spencer in the journal Nature in honor of Tarbutt. When the International Mineralogical Association was founded, tarbuttite was grandfathered as a valid mineral species.

Occurrence Tarbuttite has been found in Algeria, Angola, Australia, Canada, China, Namibia, the United States, and Zambia. Tarbuttite forms as secondary mineral in oxidized zinc deposits. It has been found in association with cerussite, descloizite, hemimorphite, hopeite, hydrozincite, "limonite", parahopeite, pyromorphite, scholzite, smithsonite, and vanadinite.

See also List of minerals named after people

References

Bibliography Cocco, G.; Fanfani, L.; Zanazzi, P. F. (1966). "The crystal structure of tarbuttite, Zn2(ОH)РО4" (PDF). Zeitschrift für Kristallographie. 123 (5): 321–329. doi:10.1524/zkri.1966.123.16.321. S2CID 96221726. Palache, P.; Berman H.; Frondel, C. (1960). "Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)" John Wiley and Sons, Inc., New York, pp. 869–871. Spencer, L. J. (April 1908). "On Hopeite and other zinc phosphates and associated minerals from the Broken Hill mines, North-Western Rhodesia" (PDF). Mineralogical Magazine. 15 (68). The Mineralogical Society: 1–38. Bibcode:1908MinM...15....1S. doi:10.1180/minmag.1908.015.68.02. Archived from the original (PDF) on 2014-01-06. Retrieved 2012-07-14.

Further reading Richmond, Wallace E. (December 1938). "Tarbuttite" (PDF). American Mineralogist. 23 (12). Mineralogical Society of America: 881–893.

External links Media related to Tarbuttite at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Tarbuttite

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

In research: Tarbuttite 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 Tarbuttite 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: Tarbuttite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hydroxide minerals, Minerals described in 1907, Minerals in space group 2, so understanding it makes those chapters shorter.
In everyday life: Look for Tarbuttite 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 Tarbuttite in 20 minutes

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

Frequently asked questions

What is Tarbuttite in simple terms?

Tarbuttite is a rare phosphate mineral with formula Zn2(PO4)(OH). It was discovered in 1907 in what is now Zambia and named for Percy Coventry Tarbutt.

Why does Tarbuttite 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 Tarbuttite?

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 Tarbuttite.