science

Tiger's eye

Tiger's eye is a 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 Tiger's eye rather than just read about it. In short: Tiger's eye (also called tiger eye) is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown colour and a silky lustre. As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite.

Key takeaways

Tiger's eye belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tiger's eye to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tiger's eye from memory before moving on to harder problems.

Reference excerpt

Tiger's eye (also called tiger eye) is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown colour and a silky lustre. As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite.

Other forms of tiger's eye Tiger iron is an altered rock composed chiefly of tiger's eye, red jasper and black hematite. The undulating, contrasting bands of colour and lustre make for an attractive motif and it is mainly used for jewellery-making and ornamentation. Tiger iron is a popular ornamental material used in a variety of applications, from beads to knife hilts. Tiger iron is mined primarily in South Africa and Western Australia. Tiger's eye is composed chiefly of silicon dioxide (SiO2) and is coloured mainly by iron oxide. The specific gravity ranges from 2.64 to 2.71. It is formed by the alteration of crocidolite. Serpentine deposits in the US states of Arizona and California can have chatoyant bands of chrysotile, a form of asbestos, fibres. These have been cut and sold as "Arizona tiger-eye" and "California tiger's eye" gemstones. The trade name 'pietersite' is used for a fractured or brecciated chalcedony containing amphibole fibers and promoted as tiger's eye from Namibia and China.

Sources Common sources of tiger's eye include Australia, India, Myanmar, Namibia, South Africa, the United States, Brazil, Canada, China, Korea and Spain.

Cultural associations In some parts of the world, the stone is believed to ward off the evil eye. Roman soldiers wore engraved tigers eye to protect them in battle.

Cut, treatment and imitation Gems are usually given a cabochon cut to best display their chatoyance. Red stones are developed by gentle heat treatments. Dark stones are artificially lightened to improve colour using a nitric acid treatment. Honey-coloured stones have been used to imitate the more valued cat's eye chrysoberyl, cymophane, but the overall effect is often unconvincing. Artificial fibre optic glass is a common imitation of tiger's eye, and is produced in a wide range of colours.

Raw and processed tiger's eye

References

External links

"New interpretation of the origin of tiger's-eye: Comment and Reply". doi:10.1130/0091-7613-32.1.e45.

Illustrations

Worked examples

Example 1 — a first encounter with Tiger's eye

Start with the simplest possible case. Write down what Tiger's eye claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In 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 Tiger's eye 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 Tiger's eye 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 Tiger's eye

In research: Tiger's eye appears in 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 Tiger's eye 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: Tiger's eye is common in secondary-school and first-year university syllabi. It links to neighbouring topics Quartz gemstones, so understanding it makes those chapters shorter.
In everyday life: Look for Tiger's eye 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 Tiger's eye in 20 minutes

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

Frequently asked questions

What is Tiger's eye in simple terms?

Why does Tiger's eye matter?

Because it connects several 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 Tiger's eye?

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 Tiger's eye.