Mineral ID 2

GEOL 1114 Mineral ID Lab 2 Fall 2020 Due 09/07/2020 Sample Name Cleavage directions & angle (example: 3 not at 90°) Luster (M or N) Color Streak Hardness Other Observations (acid reaction, elasticity, etc.) Biotite 1 direction of cleavage M Black/Gray No Streak Softer than 2.5 Biotite breaks very easily. Very flat mineral. Calcite 3 directions of cleavage N White No Streak Stronger than 2.5 but, softer than 5.5 Outside of rock is very glossy white. For the most part, Calcite is very smooth. Fluorite 3 directions of cleavage N Grayish white No Streak Stronger than 2.5 but, softer than 5.5 Outside of rock looks like a rock but when cracked open, it looks like crystals inside. Very neat looking. Galena 2 directions of cleavage M Black Black Stronger than 2.5 but, softer than 5.5 Galena has a very Metallic look. Outside of rock is matte black but inside of the rock is a very metallic look. Leaves residue on your fingers Gypsum 3 directions of cleavage N White White Softer than 2.5 Gypsum is very see through. Very flat Mineral. Streak looks like chalk residue. Halite 3 directions of cleavage N Clear White Softer than 2.5 Halite is Clear. You can see pieces of black stuff in the mineral itself. Halite is also known as salt. Hornblende 2 directions of cleavage N Black Light Gray Stronger than 2.5 but, softer than 5.5 The rock has a lot of vertical lines throughout the whole face. Very shiny rock almost metallic look. Muscovite 1 direction of cleavage N Clear No Streak Softer than 2.5 Our sample of Muscovite looks exactly like glass. A little more flexible than glass but looks just like it. Plagioclase Feldspar 4 Directions of cleavage N White No streak Stronger than 5.5 Rock is mainly white. There is a piece on the rock that has a metallic look. Weird how its just a small piece of the rock.