earth science

Laumontite

Laumontite 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 Laumontite rather than just read about it. In short: Laumontite is a mineral, one of the zeolite group. Its molecular formula is CaAl2Si4O12·4H2O, a hydrated calcium-aluminium silicate.

Key takeaways

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

Reference excerpt

Laumontite is a mineral, one of the zeolite group. Its molecular formula is CaAl2Si4O12·4H2O, a hydrated calcium-aluminium silicate. Potassium or sodium may substitute for the calcium but only in very small amounts. It is monoclinic, space group C2/m. It forms prismatic crystals with a diamond-shaped cross-section and an angled termination. When pure, the color is colorless or white. Impurities may color it orange, brownish, gray, yellowish, pink, or reddish. It has perfect cleavage on [010] and [110] and its fracture is conchoidal. It is very brittle. The Mohs scale hardness is 3.5-4. It has a vitreous luster and a white streak. It is found in hydrothermal deposits left in calcareous rocks, often formed as a result of secondary mineralization. Host rock types include basalt, andesite, metamorphic rocks and granites. It forms at a temperature of about 100 °C (212 °F), and becomes unstable above about 150 °C (302 °F), and so its presence in sedimentary rocks indicates that these have experienced intermediate diagenesis. The identification of laumontite goes back to the early days of mineralogy. It was first named lomonite by R. Jameson (System of Mineralogy) in 1805, and laumonite by René Just Haüy in 1809. The current name was given by K.C. von Leonhard (Handbuch der Oryktognosie) in 1821. It is named after Gillet de Laumont who collected samples from lead mines in Huelgoat, Brittany, making them the type locality. Laumontite easily dehydrates when stored in a low humidity environment. When freshly collected, if it has not already been exposed to the environment, it can be translucent or transparent. Over a period of hours to days the loss of water turns it opaque white. In the past, this variety has been called leonhardite, though this is not a valid mineral species. The dehydrated laumontite is very friable, often falling into a powder at the slightest touch. It is a common mineral, found worldwide. It can be locally abundant, forming seams and veins. It is frequently associated with other zeolites, including stilbite and heulandite. Notable occurrences are India; Paterson, New Jersey; Pine Creek, California; Iceland; Scotland; and the Bay of Fundy, Nova Scotia. Prehnite pseudomorphs after laumontite (epimorphs) have been found in India.

References

Mindat Laumontite Webmineral Laumontite IMA Zeolite Classification

External links Structure type LAU

Illustrations

Worked examples

Example 1 — a first encounter with Laumontite

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

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

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

Frequently asked questions

What is Laumontite in simple terms?

Laumontite is a mineral, one of the zeolite group. Its molecular formula is CaAl2Si4O12·4H2O, a hydrated calcium-aluminium silicate.

Why does Laumontite 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 Laumontite?

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 Laumontite.