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Minerals

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A mineral is a naturally occurring chemical compound usually of crystalline form and not produced by life processes. A mineral has one specific chemical composition, whereas a rock can be an aggregate of different minerals or mineraloids. The study of minerals is called mineralogy. To meet the definition of “mineral” used by most geologists, a substance must meet five requirements:

Moonstone

Moonstone is a type of feldspar mineral that has a unique adularescent effect, meaning it displays a shimmering, floating light effect that appears to...

Onyx

The Geological Origin, History, Layered Structure and Why This Dark, Banded Stone Has Been Valued for CenturiesOnyx is a stone that leaves a heavy,...

Bentonite

Bentonite is a type of clay that is composed primarily of the mineral montmorillonite. It is a highly absorbent clay that has many uses...

Illite

Illite is a type of clay mineral that belongs to the group of non-expanding or non-swelling phyllosilicate minerals. It is a common constituent of...

Smectite

Smectite minerals are a group of phyllosilicate minerals that are characterized by a layered structure and the ability to swell when exposed to water....

Alexandrite

Among all gemstones studied by mineralogists and gemologists, alexandrite remains one of the most scientifically fascinating. It is a variety of the mineral chrysoberyl...

Jadeite

Jadeite is a mineral that belongs to the pyroxene group, which is a group of rock-forming silicate minerals. It is one of two types...

Emerald

Emerald are a type of gemstone that belong to the beryl family, which has the chemical formula Be3Al2(SiO3)6. They are valued for their intense...

Ruby

Ruby is a gemstone and a variety of the mineral corundum (Al2O3) that is distinguished by its red color, which is caused by trace...

Sapphire

Sapphire is a precious gemstone that is a variety of the mineral corundum, which is composed of aluminum oxide. It is typically blue in...

Agate

Agate is a fascinating and versatile mineral that has captivated human interest for thousands of years. Agate is a variety of chalcedony, a mineral...

Chalcedony

Chalcedony is a mineral that is composed of microscopic crystals of quartz. It is a cryptocrystalline form of silica, meaning that its crystals are...

15 Naturally Striped and Banded Rocks

Some rocks in nature display remarkable patterns of stripes, wavy bands, and contrasting layers, almost as if they had been painted by an artist....

Rocks That Float on Water: Types, Formation, and Examples

When you drop a rock into water, you usually expect it to sink. Most rocks are denser than water, so they quickly settle to...

Why Is My Rock Magnetic? 8 Common Magnetic Rocks and Minerals

When you bring a magnet close to a rock and notice that it is strongly attracted, the result can be surprising. If the rock...