1. The book says:
After the Earth formed, the planet’s interior became so hot that magma formed. Lava repeatedly flowed over the surface and hardened, forming a rocky crust. That crust sank into Earth’s interior, allowing more lava to erupt over the surface and harden to form rock.
Ms. Krupa says:
The Earth’s crust is made out of rock, which came from magma deep below the Earth’s surface.
Magma and lava are the same thing; magma is
INSIDE the earth, lava is
ON the surface.
2. The book says:
Igneous comes from the Latin word ignis, meaning “fire”
Igneous rocks are classified according to their origin, texture, and mineral composition
Ms. Krupa says:
Igneous rocks are classified (sorted) by where they come from, their texture, and what minerals they are made of.
3. The book says:
Extrusive rock is igneous rock formed from lava that erupted onto Earth’s surface. Basalt is the most common extrusive rock. Basalt forms much of the crust, including the oceanic crust.
Ms. Krupa says:
the exterior (outside) of the
Earth. They are made of lava.
Example: Basalt – makes up the part of Earth’s crust sitting under the oceans
4. The book says:
Igneous rock that formed when magma hardened beneath the Earth’s surface is called intrusive rock. The most abundant intrusive rock in the continental crust is granite.
Ms. Krupa says:
the interior (inside) of the
Earth. They are made of magma.
Example: Granite – makes up the “land” part of Earth’s crust

5. The book says:
The texture of an igneous rock depends on the size and shape of its mineral crystals. Rapidly cooling lava forms fine-grained igneous rocks with small crystals. Slowly cooling magma forms coarse-grained rocks with large crystals. Therefore, intrusive and extrusive rocks usually have different textures.
Ms. Krupa says:
Inside of the Earth, magma cools slowly, allowing large crystals to form inside of intrusive igneous rocks.
On the surface, lava cools quickly, so smaller crystals form. Sometimes the lava cools so fast, that NO crystals form
.
6. The book says:
A rocks mineral composition determines its color
Ms. Krupa says:
The same type of rock can look different than others of its kind, depending on what minerals it is made of.
7. The book says:
People throughout history have used igneous rock for tools and building materials. The ancient Egyptians used granite for statues. The Incas of Peru carefully fitted together great blocks of granite and other igneous rocks to build a fortress near Cuzco, their capital city. The US used granite in buildings, bridges, and to pave streets in the 1800s and early 1900s. Today, thin, polished sheets of granite are used in curbstones, floors, and kitchen counters. Basalt is crushed to make gravel that is used in construction. Pumice is a good abrasive used in cleaning and polishing. Ancient
Native Americans used obsidian to make sharp tools for cutting and scraping.
Ms. Krupa says:
Igneous rocks have had many uses throughout history and today. Some uses are: building materials and tools.
Pumice is an extrusive rock that is very light and can be ground down and used in abrasives, cleaners, even pencil erases and toothpaste. It’s often used for pedicures to exfoliate dry skin.