earth science

Whiteite

Whiteite 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 Whiteite rather than just read about it. In short: Whiteite is a rare hydrated hydroxyphosphate mineral. Whiteite subgroup The name whiteite refers to three minerals in the jahnsite-whiteite group, whiteite subgroup.

Key takeaways

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

Reference excerpt

Whiteite is a rare hydrated hydroxyphosphate mineral.

Whiteite subgroup The name whiteite refers to three minerals in the jahnsite-whiteite group, whiteite subgroup. Subgroup members (formulae from IMA):

Whiteite-(CaFeMg), IMA1975-001, CaFe2+Mg2Al2(PO4)4(OH)2·8H2O Whiteite-(MnFeMg), IMA1978-A, Mn2+Fe2+Mg2Al2(PO4)4(OH)2·8H2O Whiteite-(CaMnMg), IMA1986-012, CaMn2+Mg2Al2(PO4)4(OH)2·8H2O Rittmannite, Mn2+Mn2+Fe2+2Al2(PO4)4(OH)2·8H2O In the whiteite formulae, the symbols in brackets indicate the dominant atom in three distinct structural positions, designated X, M(1), and M(2), in that order; for instance, magnesium Mg is always the dominant atom in the M(2) position for all the whiteite minerals. Whiteite was named after John Sampson White Jr (born 1933), associate curator of minerals at the Smithsonian Institution, and founder, editor and publisher (1970–1982) of the Mineralogical Record.

Unit cell All members of the series belong to the monoclinic crystal system with point group 2/m. Most sources give the space group as P21/a for the Ca Fe rich member, which was the first of the series to be described, but Dana gives it as P2/a. The other members are variously described in different sources as having space groups P21/a, P2/a or Pa. There are two formula units per unit cell (Z = 2). The cell parameters vary slightly between the group members, but to the nearest angstrom they all have a = 15 Å, b = 7 Å and c = 10 Å, with β 112.5 to 113.4. Individual values are:

Whiteite-(CaFeMg) a = 14.90 Å, b = 6.98 Å, c = 10.13 Å, β = 113.12 Whiteite-(MnFeMg) a = 14.99 Å, b = 6.96 Å, c = 10.14 Å, β = 113.32 Whiteite-(CaMnMg) a = 14.842 Å, b = 6.976 Å, c = 10.109 Å, β = 112.59

Appearance The whiteite minerals are generally brown, pink or yellow, and whiteite-(CaMnMg) may also be light lavender coloured. They are transparent to translucent, with a vitreous luster and a white to brownish white streak. They occur as aggregates of tabular crystals, or thick tabular canoe-shaped crystals. Whiteite from Rapid Creek in the Yukon, Canada, is often associated with deep blue lazulite crystals (33 out of 49 photos on Mindat.org).

Optical properties The optical class is thought to be biaxial (+), but whiteite-(CaFeMg) may be biaxial (−). The refractive indices are Nx = 1.580, Ny = 1.584 to 1.585 and Nz = 1.590 to 1.591, similar to those for quartz.

Physical properties Whiteite is invariably twinned, giving the crystals a pseudo-orthorhombic appearance, and the cleavage is good to perfect. Whiteite is quite soft, with hardness 3 to 4, between calcite and fluorite. Its specific gravity is 2.58, similar to that of quartz. Whiteite is not radioactive.

Occurrence The type locality for whiteite-(CaFeMg)and whiteite-(MnFeMg) is the Ilha claim, Taquaral, Itinga, Jequitinhonha valley, Minas Gerais, Brazil, and for whiteite-(CaMnMg) it is the Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer County, South Dakota, US. The type material is conserved at the National School of Mines, Paris, France, and at the National Museum of Natural History, Washington DC, US, reference 123013. At the Lavra da Ilha pegmatite, Taquaral, Brazil, whiteite is found in a complex zoned granite pegmatite associated with eosphorite, zanazziite, wardite, albite and quartz. At Blow River, the Yukon, Canada, it is found in iron-rich sedimentary rocks with siderite, lazulite, arrojadite and quartz. At Ilha de Taquaral, Minas Gerais, Brazil, it occurs along joints and fractures in quartz and albite associated with other phosphates.

References

Illustrations

Worked examples

Example 1 — a first encounter with Whiteite

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

In research: Whiteite 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 Whiteite 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: Whiteite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Calcium minerals, Iron(II) minerals, Magnesium minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Whiteite 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 Whiteite in 20 minutes

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

Frequently asked questions

What is Whiteite in simple terms?

Whiteite is a rare hydrated hydroxyphosphate mineral. Whiteite subgroup The name whiteite refers to three minerals in the jahnsite-whiteite group, whiteite subgroup.

Why does Whiteite 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 Whiteite?

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 Whiteite.