earth science

Seamanite

Seamanite 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 Seamanite rather than just read about it. In short: Seamanite, named for discoverer Arthur E. Seaman, is a rare manganese boron phosphate mineral with formula Mn3[B(OH)4](PO4)(OH)2.

Key takeaways

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

Reference excerpt

Seamanite, named for discoverer Arthur E. Seaman, is a rare manganese boron phosphate mineral with formula Mn3[B(OH)4](PO4)(OH)2. The yellow to pink mineral occurs as small, needle-shaped crystals. It was first discovered in 1917 from a mine in Iron County, Michigan, United States and identified in 1930. As of 2012, seamanite is known from four sites in Michigan and South Australia.

History In 1917, Arthur E. Seaman collected a mineral sample from the Chicagon Mine in Iron County, Michigan. He correctly believed it to be a new mineral species based on a qualitative analysis of its composition by F. B. Wilson. World War I delayed further study of the mineral until 1929. A study in 1930 proved it to be a new mineral and named it seamanite in honor of Seaman. They cited his career as a professor of geology and mineralogy and his contributions to the field as reasons for the naming. The original analysis of the mineral in 1930 suggested seamanite to be a hydrated salt. However, in 1971, the mineral was determined to be the coordination compound Mn3[B(OH)4](PO4)(OH)2.

Description Seamanite is a transparent, yellow to pink mineral that occurs as needle-shaped crystals. Seamanite is a brittle mineral with a mohs hardness of 4. It is found in the crevices of fractured siliceous rock. The type occurrence was found in association with small crystals of calcite, thin coatings of manganese oxide, and fibrous sussexite. Seamanite has also been found with shigaite.

Distribution As of 2012, seamanite is known from four locations: the Cambria-Jackson Mine in Marquette County, Michigan, the Chicagon Mine and the Bengal Mine in Iron County, Michigan, and the Iron Monarch open cut in the Eyre Peninsula, South Australia. The type material is stored at Michigan Technological University in Houghton, Michigan, and at the National Museum of Natural History in Washington, D.C. as sample 96282.

Crystallography

Seamanite is formed of acicular crystals elongated along [001] and showing the faces {110} and {111} up to one centimeter. It has an orthorhombic crystal system and the Pbnm space group. The parameters of its unit cell are: a=7.811 Å, b=15.114 Å, c=6.691 Å, Z=4 units per unit cell.

Notes

References

Bibliography Kraus, E.H.; Seaman, W.A.; Slawson, C.B. (June 1930). "Seamanite, a new manganese phospho-borate from Iron County, Michigan" (PDF). American Mineralogist. 15 (6). Mineralogical Society of America: 220–225. Retrieved April 13, 2012. Moore, Paul B.; Ghose, Subrata (September–October 1971). "A Novel Face-Sharing Octahedral Trimer in the Crystal Structure of Seamanite" (PDF). American Mineralogist. 56 (9 & 10). Mineralogical Society of America: 1527–1538. Retrieved April 13, 2012. 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. 388–389. Slawson, Chester B. (December 1934). "Sussexite from Iron County, Michigan" (PDF). American Mineralogist. 19 (12). Mineralogical Society of America: 575–578. Retrieved April 13, 2012.

Further reading Huminicki, Danielle M.C.; Hawthorne, Frank C. (2002). "Hydrogen Bonding in the Crystal Structure of Seamanite" (PDF). The Canadian Mineralogist. 40 (3): 923–928. doi:10.2113/gscanmin.40.3.923. Retrieved April 14, 2012. McConnell, Duncan; Pondrom, Walter L. Jr. (July 1941). "X-ray Crystallography of Seamanite" (PDF). American Mineralogist. 26 (7). Mineralogical Society of America: 446–447. Retrieved April 13, 2012.

External links Media related to Seamanite at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Seamanite

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

In research: Seamanite 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 Seamanite 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: Seamanite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Borate minerals, Manganese(II) minerals, Minerals in space group 62, so understanding it makes those chapters shorter.
In everyday life: Look for Seamanite 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 Seamanite in 20 minutes

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

Frequently asked questions

What is Seamanite in simple terms?

Seamanite, named for discoverer Arthur E. Seaman, is a rare manganese boron phosphate mineral with formula Mn3[B(OH)4](PO4)(OH)2.

Why does Seamanite 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 Seamanite?

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 Seamanite.