the scheme for igneous rock identification

The Scheme for The Scheme for Igneous Rock IdentificationIgneous Rock Identification

A Brief TourA Brief Tour

Crystal Crystal sizesize

DescriptionGrain size

Igneous rocks have Igneous rocks have “Intergrown Crystals”“Intergrown Crystals”

IntergrownIntergrown

IntergrownIntergrown

IntergrownIntergrown

Not IntergrownNot Intergrown

Where it was formedWhere it was formedOutside the volcano: ExtrusiveInside the Earth: Intrusive

BubblesBubbles?? Yes= Vesicular

BubblesBubbles??

No=Non-vesicular

ColorColorVery Light

LightNotVery LightNot Very Dark

DarkVery Dark

Neither Light nor Dark

Lightest

Darkest

DensityDensityVery Light

Light DenseVery Dense

Medium Density

Finding The MineralsFinding The MineralsIdentify the rock.

Unless you have other information, work in the middle of the rock’s box.

This is the amount of Potassium Feldspar in the rock.

This is the amount of Quartz in the rock.

This is the amount of Plagioclase Feldspar in the rock.

Use tick marks on a scrap paper to measure the percentage.Potassium Feldspar 25%Quartz 40%

PracticePractice Name a light-colored, glassyrock with no bubbles.

Name a coarse-grained, dense rock.

Name a dark colored , dense rock that can be intrusive or extrusive