Mineral Identification Labs
Mineral Identification Labs
Despite its name, the goal of the assignment was not necessarily to identify the correct mineral. This is why I enjoyed it so much. Rather than getting the correct answer, the most important part of this lab was the process. When learning about minerals, this is important for students to understand. While the goal is to get the correct answer, doing the steps correctly and identifying the correct components of the mineral will get eventually get the student to that point.
As described by the Mineral ID Lab Assignment, in regard to minerals, this process includes looking at:
Overall Observation:
The Loupe or Magnifiers are must-have accessories hanging around the neck of every geologist and rock-hound. 10x magnification lets you get up and personal with rocks and minerals. Magnifying loupes allow you to really view minerals and the mineral crystals making up rocks. This is an important tool in rock and mineral identification. Focus your attention through the lens... what do you see?
Color, Streak, and Luster:
Diamonds have many valuable properties. Diamonds are extremely hard and are used for industrial purposes. The most valuable diamonds are large, well-shaped, and sparkly. Turquoise is another mineral that is used in jewelry because of its striking greenish-blue color. Many minerals have interesting appearances. Specific terms are used to describe the appearance of minerals.
To find color:
What is the overall hue of the mineral?
To find streak:
Drag the mineral along a piece of marble. If there is a streak left, what is the color?
To find luster:
Does the mineral appear glassy, pearly, earthy, metallic, etc.?
Heft:
To the best of your ability, describe the mineral's density. Density describes how much matter is in a certain amount of space. Substances that have more matter packed into a given space have higher densities. Density and Specific Gravity are not properties easily determined, requiring special equipment; but a result of them, which might simply be called "heft" can come in handy: The denser a mineral is, the heavier it is per given volume. So a mineral's "heft" can be a clue to its identity.
Hardness:
Hardness is a mineral's ability to resist being scratched. Minerals that are not easily scratched are hard. You test the hardness of a mineral by scratching its surface with a mineral of known hardness. Mineralogists use the Mohs Hardness Scale, used as a reference for mineral harndess. The scale lists common minerals in order of their relative hardness. You can use the minerals in the scale to test the hardness of an unknown mineral. Refer to the image below for the Mohs Hardness Scale.
Fracture/Cleavage:
Cleavage is the tendency of a mineral to break along certain planes. When a mineral breaks along a plane it makes a smooth surface. Fracture describes how a mineral breaks without any pattern. A fracture is uneven. The surface is not smooth and flat.
Reaction to Acid:
If the given mineral is scratched with a penny and drops of acid are placed on the scratch-mark, does the mineral react?
Other Identifying Characteristics:
Minerals have other properties that can be used for identification. For example, a mineral’s shape may indicate its crystal structure. Sometimes crystals are too small to see. Then a mineralogist may use a special instrument to find the crystal structure. Some identifying characteristics are listed in the image below.
My final answer key for the assignment:
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