what is mineral's sreak and why is streak more reliable property than color in mineral
assistance needed
A mineral's streak refers to the color of its powdered form, which is obtained by rubbing the mineral on a porcelain plate or a streak plate. The streak color can sometimes be different from the mineral's actual color, which is why it is considered a more reliable property than color alone when identifying minerals. Here's why:
1. Consistency: The color of a mineral's streak tends to be more consistent than its outer color. The outer color can be influenced by impurities or chemical reactions, leading to variations in color. On the other hand, the powdered form reveals the mineral's true or characteristic color, making it more reliable in identification.
2. Transparency: Some minerals may appear colorless or have a similar outward color, making it difficult to differentiate between them. However, when these minerals are streaked, their true colors can be revealed, aiding in their identification.
3. Hardness: During streak testing, the mineral is scraped against the streak plate, which is typically made of unglazed porcelain. The hardness of the mineral can affect the resulting streak color. So, by observing the hardness of the mineral and the color of the streak, you can gather additional information about the mineral's properties.
To determine a mineral's streak, you can follow these steps:
1. Choose a streak plate or a piece of unglazed porcelain tile.
2. Hold the mineral firmly and rub it against the streak plate with enough pressure to create a streak.
3. Observe the color left behind by the mineral on the streak plate. It may be different from the mineral's outer color.
4. Compare the streak color obtained with known streak colors of various minerals to help identify the mineral in question.
By considering the streak color along with other mineral properties like hardness, cleavage, luster, and crystal shape, you can gain a more accurate identification.