Melina briefly touched on this, but I thought I would review how you identify a mineral! (The picture is of the mineral Galena.)
Color: The color of the mineral itself, it is helpful to be a specific as possible when describing this, however the color can sometimes be misleading!
Streak: Be careful! The streak is not the same as the color. The streak is the color of the line left behind when the mineral is scraped against a porcelain plate. It is possible for a mineral to leave no streak behind!
Luster: Generally the luster of a rock can be either metallic or non-metallic. But in the non-metallic subgroup there are many different types of luster. Subvitreous (less brilliant than glass), vitreous (like glass), admantine (similar to diamond), Resinous (similar to the luster of resin), Earthy (is a dull surface that has no shine), greasy (it feels as if it is covered in oil or grease), Pearly (like pearl), or silky (this will have a subtly shiny appearance similar to silk).
Hardness: To test the hardness you scrape the mineral along a variety of substances (examples include your fingernail, a penny, glass, porcelain) and see if the mineral can leave a scratch.
Cleavage: Cleavage is the way the mineral will break. Many minerals break along cleavage planes, which are flat surfaces. A mineral's cleavage can either be perfect, good or poor.
Magnetism: This is a pretty obvious one to test. It can either be strong, moderate, weak, or there can be none. The most well known mineral with poor magnetism is magnetite.
Reaction to acid: After putting HCl on a mineral the reaction will either be vigorous, some or no reaction. Out of the minerals we have tested, only calcite has a an acid reaction (this is why limestone reacts to HCl).
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