earth science

Goldmanite

Goldmanite 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 Goldmanite rather than just read about it. In short: Goldmanite is a green or greenish-brown silicate mineral of the garnet group with a chemical formula of Ca3(V3+,Al,Fe3+)2(SiO4)3. Discovery It was first described in 1964 for an occurrence in the Laguna District, Cibola County, New Mexico and is named after Marcus Isaac Goldman (1881–1965), an American petrologist.

Key takeaways

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

Reference excerpt

Goldmanite is a green or greenish-brown silicate mineral of the garnet group with a chemical formula of Ca3(V3+,Al,Fe3+)2(SiO4)3.

Discovery It was first described in 1964 for an occurrence in the Laguna District, Cibola County, New Mexico and is named after Marcus Isaac Goldman (1881–1965), an American petrologist. The type locality, South Laguna (or Sandy) mine area, was in vanadium rich clay within a metamorphosed uranium-vanadium deposit in sandstone. While studying these deposits, it was noted that garnet in relatively unmineralized sandstone is colorless, whereas garnet in dark well-mineralized rock, containing abundant vanadium clay and uranium deposits was deep green or brownish green. To confirm the green color was due to vanadium, two samples of garnet were separated from dark ore, analyzed, and found to be rich in vanadium. The South Laguna mine area was studied in 1955 and 1956 as part of an investigation of the geology and uranium deposits of the Laguna district by the USGS.

Occurrence In addition to the type location in the Sandy mine in New Mexico, it has been reported from Coat-an-Noz, Cotes-du-Nord, France; in drill core from the North Sea; from Klatovy, Czech Republic; Ishimskaya Luka, northern Kazakhstan; the Slyudyanka complex, Sayan Mountains, near Lake Baikal region of Russia and the Yamoto mine, Kagoshima Prefecture, Japan. One of the world's biggest goldmanite deposits can be found in the Pezinok District, Slovakia. It is also found in the metalliferious black shales of the Korean Peninsula.

Composition Goldmanite is composed of calcium (24.79%), aluminium (3.34%), vanadium (12.6%), iron (2.3%), silicon (17.37%), and oxygen (39.59%). Its chemical formula is Ca3(V3+,Al,Fe3+)2(SiO4)3.

Properties The approximate density (3.74±.03) of goldmanite was determined by finding the density of diluted Clerici solution in which small fragments remained suspended. Because of fine grain size, more accurate determination of density was not attempted. The calculated density (3.737) agrees with the approximate value. The index of refraction was found by immersion to be 1.821±.001, using sodium light and adjusting for small temperature changes. Like so many calcium garnets, goldmanite was found to be weakly anisotropic. The cell edge of goldmanite is 12.011 Å, as determined by x-ray powder diffraction analysis.

References

Illustrations

Worked examples

Example 1 — a first encounter with Goldmanite

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

In research: Goldmanite 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 Goldmanite 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: Goldmanite is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cubic minerals, Garnet group, Minerals in space group 230, so understanding it makes those chapters shorter.
In everyday life: Look for Goldmanite 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 Goldmanite in 20 minutes

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

Frequently asked questions

What is Goldmanite in simple terms?

Goldmanite is a green or greenish-brown silicate mineral of the garnet group with a chemical formula of Ca3(V3+,Al,Fe3+)2(SiO4)3. Discovery It was first described in 1964 for an occurrence in the Laguna District, Cibola County, New Mexico and is named after Marcus Isaac Goldman (1881–1965), an Amer…

Why does Goldmanite 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 Goldmanite?

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 Goldmanite.