earth science

Gmelinite

Gmelinite 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 Gmelinite rather than just read about it. In short: Gmelinite is a series of rare zeolite minerals. The most common member is gmelinite-Na; others are gmelinite-Ca and gmelinite-K.

Key takeaways

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

Reference excerpt

Gmelinite is a series of rare zeolite minerals. The most common member is gmelinite-Na; others are gmelinite-Ca and gmelinite-K. It is closely related to the very similar mineral chabazite. Gmelinite was named as a single species in 1825 after Christian Gottlob Gmelin (1792–1860) professor of chemistry and mineralogist from Tübingen, Germany, and in 1997 it was raised to the status of a series.Gmelinite-Na has been synthesised from Na-bearing aluminosilicate gels. The naturally occurring mineral forms striking crystals, shallow, six sided double pyramids, which can be colorless, white, pale yellow, greenish, orange, pink, and red. They have been compared to an angular flying saucer.

Structure The aluminosilicate framework is composed of tetrahedra linked to form parallel double six-membered rings stacked in two different positions (A and B) in the repeating arrangement AABBAABB. The framework has no Al-Si order. Within the structure there are cavities with a cross-section of up to 4 Å, and also wide channels parallel to the c axis with a diameter of 6.4 Å. Space group: P63/mmc. Unit cell parameters: a=13.72 Å, c=9.95 Å, Z=4.

Environment Generally occurs in Si-poor volcanic rocks, marine basalts and breccias, associated with other sodium zeolites such as analcime, Na(Si2Al)O6·H2O, natrolite, Na2(Si3Al2)O10·2H2O, and chabazite-Na, Na2Ca(Si8Al4)O24·12H2O. It also occurs in Na-rich pegmatites in alkaline rocks, and as an alteration product in some nepheline syenite intrusions. No sedimentary gmelinite has been found. It is generally assumed that it forms at low temperatures, less than 100 °C. It is widespread as a hydrothermal alteration product of ussingite, Na2AlSi3O8(OH), associated with gobbinsite, Na5(Si11Al5)O32·11H2O, gonnardite, (Na,Ca)2(Si,Al)5O10·3H2O, and chabazite-K.

Notable localities Gmelinite-Na occurs extremely rarely at the Francon Quarry, Montreal, Canada, in sills of the igneous volcanic rock phonolite which are rich in dawsonite, NaAl(CO3)(OH)2. It occurs both as pure gmelinite-Na and interlayered with chabazite in water-quenched basalts in Western Tasmania. Associated minerals include other zeolites, especially chabazite, quartz, aragonite and calcite.

Distribution Type Locality: Monte Nero, San Pietro, Montecchio Maggiore, Vicenza Province, Veneto, Italy. Also found in Australia, Canada, Czech Republic, Germany, Hungary, Japan, Russia, UK and US.

References

External links Structure type GME Mineral galleries Mindat

Illustrations

Gmelinite: Gmelinite from Ireland — Gmelinite from Ireland

Worked examples

Example 1 — a first encounter with Gmelinite

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

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

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

Frequently asked questions

What is Gmelinite in simple terms?

Gmelinite is a series of rare zeolite minerals. The most common member is gmelinite-Na; others are gmelinite-Ca and gmelinite-K.

Why does Gmelinite 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 Gmelinite?

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 Gmelinite.