PROPERTIES OF ROCKS
1. COLORS: 1. Rocks are different colors because
they have minerals. The color of the minerals in the rock can turn it brown, red, green or other colors.
2. SIZES:
Why are rocks different sizes?
Boulders are the biggest type of rock, to be found on a mountain. A boulder is so big that most humans can't move them on their own.
A cobble is a rock that is smaller than a boulder and larger than a pebble
A rock is smallest when it is turned into silt. Silt is smaller than sand and often found at the bottom of rivers and streams.
3. SHAPES:3. Why are rocks different shapes?
Rocks are different shapes because they are hit over and over by water and wind.
4. TEXTURE: Rock's texture—coarse-grained, fine-
grained, and glassy are all descriptions of a rock's texture. The texture of igneous rocks can be analyzed to understand how the rock became solid or crystallized from liquid, melted rock.
COARSE-GRAINED
GLASSY TEXTURE
FINE-GRAINED
5. HARDNESS:Rating Description Mineral Example :
1 Very Soft Easily crumbles. Can be scratched with a fingernail (2.2) Talc
2 Soft Can be scratched with a fingernail (2.2) Gypsum, Soapstone
3 Soft Can be scratched with a copper penny (3.5) Calcite
4 Semi-Hard Can be scratched with a common nail (5.2) Fluorite
5 Hard Can be scratched with a common nail (5.2). Apatite
6 Hard N. B. Mineral of hardness 6 or more will scratch glass. Feldspar
7 Very Hard Can be scratched with a concrete
8 Very Hard Topaz 9 Extremely Hard Used in industrial
tools for cutting, grinding & sanding. Corundum
10 The Hardest Diamond is used to cut all minerals including diamonds. Diamond
6. HEAVINESS
Rocks are measured through their mass. It can be considered light or heavy.