The video tutorial discusses cleavage and fracture in minerals, explaining how minerals break along cleavage planes or fracture irregularly. It covers the types of cleavage, such as in mica and feldspar, and distinguishes between cleavage and parting. The tutorial also explores fracture types, including even, uneven, hackly, splintery, fibrous, and conchoidal, highlighting their significance in mineral identification and historical tool-making.

What is the primary reason for the softness of graphite?

• Its hexagonal sheets of carbon

• Its cubic structure

• Its chemical composition

• Its weak planes

What is cleavage in minerals?

• Breaking along rough surfaces

• Breaking along irregular surfaces

• Breaking along smooth planar surfaces

• Breaking along curved surfaces

Which mineral is known to have cleavage in zero direction?

• Amphibole

• Quartz

• Feldspar

• Mica

How many cleavage directions does Galena have?

• One

• Two

• Three

• Four

What is the angle between the two cleavages in amphibole?

• 90 degrees

• 93 degrees

• 120 degrees

• 124 degrees

What is parting in minerals caused by?

• Chemical composition

• External pressure

• Crystallographic imperfections

• Weak atomic structure

Tags

NGSS.MS-PS1-1

Which mineral shows parting due to twin planes?

• Corundum

• Quartz

• Feldspar

• Mica

What type of fracture is characterized by a nearly flat shape?

• Even

• Hackly

• Uneven

• Splintery

Which type of fracture is shown by minerals like kyanite?

• Splintery

• Hackly

• Uneven

• Even

What type of fracture did early humans use to carve stone tools?

• Fibrous

• Uneven

• Even

• Conchoidal