Unit 2E A Rocks & Minerals

Unit 2E A Rocks & Minerals

1. Minerals

Minerals are solid substances formed in nature Vocabulary minerals A solid substance formed in natured

Minerals are made of materials that were never alive A mineral always has the same chemical make-up

The atoms of a mineral are arranged in regular patterns and form shapes called crystals

Vocabulary: crystals A solid in which the atoms are arranged in regular patterns

Most minerals are formed by magma Vocabulary Magma The hot liquid rock inside Earth

When magma cools slowly, minerals with large crystals are formed

When magma cools quickly minerals with small crystals form Dolerite Gabbro

There are about 3,000 different minerals on Earth Some minerals, like sulfur, are made up of one kind of atom

Others, like quartz, are made of more than one kind of atom

Minerals have properties that can be used to identify them One of these properties is streak

Vocabulary streak The color of a mineral when it is in powdered form

Sulfur is always yellow Other minerals, like quartz, may be found in many colors

Luster, cleavage, and hardness are other properties used to identify minerals

Vocabulary: luster Describes how shiny a mineral is when light hits it

Some minerals, like sulfur, are dull Some minerals, like gold, are very shiny

Vocabulary: cleavage The way a mineral breaks

Mica breaks in one direction and forms sheets Sulfur breaks into many uneven pieces

Vocabulary: hardness The ability of a mineral to be scratched

Some minerals are so soft that they can be scratched by a fingernail Diamond, the hardest mineral, can scratch any other mineral

In 1824, Friedrich Mohs developed a list of common minerals to compare their hardness called the Mohs Scale “Click me and I will sing for you” Says Taylor

Unit 2E A Rocks & Minerals