Amethyst
- students explore the properties of earth's minerals
- students can use properties to identify some minerals
- students actively explore crystalization of minerals.
Dates to Remember
March 11 : Properties of minerals - Title page due
March 12: Identifying minerals
March 13 : Set up activity page 362. Growing crystals and crystal shapes
March 14 : Observations of growing crystal. Analysis Quesions page 363 - due Monday: March 18.
March 15: Quiz and Video
New words:
Crust: refers to a very thin outermost layer of the Earth.
Element: a pure substance e.g. hydrogen.
Compound: two or more elements combined e.g. qartz (silicon and oxygen).
Mineral: an inorganic naturally occurring substance that can be made up of one element or a combination (compound). Most minerals are quite rare. The rarest minerals are gem stones.
Common minerals that form the bulk of the earth's crust: quartz, feldspar, biotite, calcite.
Mohs Hardness Scale: a method of identifying minerals based on the property of hardness. A German scientist, Friedrich Mohs, developed a ten mineral scale with a hardness value of 1 to 10.
Lustre: a property of minerals that describes how the light is reflected from the surface. Minerals can be dull, shiny, greasy, metallic, non-metalic.
Colour: some minerals can be identified by their attractive colours. Some minerals can be different colours, depending on the impurities that are in the mineral, e.g. quartz is white when pure, but is purple when impure, and becomes the gem stone known as amethyst.
Streak: When a mineral is rubbed across a piece of unglazed tile, it leaves a streak (the colour of the power). Look-alike minerals can be distinguished in this way, e.g. gold has a gold streak, but pyrite has a black streak. A tile has a hardness of 7, so any mineral harder than that will not leave a streak.
Cleavage: When a mineral breaks along a smooth, flat surface, it is said to have cleavage, e.g. mica (biotite and muscovite) have a flat cleavage that allows them to break into thin pieces.
Fracture: Minerals that break with rough or jagged edges have fracture e.g quatz.
Crystal: the building blocks of mineral, crystals occur natually and have straight edges, flat sides and regular angles.
Rock: a natural material composed of one or more minerals.
Resources: Text Book pages 352-441
- The mineral and gem kingdom (sorts all minerals by characteristics)
- Minerals by name
- Mohs hardness scale
- Periodic table of elements
Pyrite (fool's gold)
Biotite
Quartz
Halite crystal (cubic system)
Corundum crystal (hexagonal): very hard mineral (9)
Gypsum (monoclinic) : very soft mineral (2)