Table of Contents
- 1 What minerals can be scratched by Gypsum?
- 2 What is the hardness of a mineral that scratches Gypsum?
- 3 What is gypsum used in?
- 4 What is the hardness of gypsum?
- 5 How can minerals be identified?
- 6 Is gypsum a mineral?
- 7 What is the hardest mineral that can scratch?
- 8 What minerals can be scratched by a knife?
What minerals can be scratched by Gypsum?
A mineral or other material with a higher hardness number can scratch anything with an equal or lower number. Thus, a copper penny can scratch calcite, gypsum and talc, while a fingernail can scratch only gypsum and talc.
What is the hardness of a mineral that scratches Gypsum?
2
You find that calcite scratches the gold. Gypsum does not. Gypsum has a hardness of 2 and calcite is a 3. That means the hardness of gold is between gypsum and calcite….Mohs Hardness Scale.
| Hardness | Mineral |
|---|---|
| 2 | Gypsum |
| 3 | Calcite |
| 4 | Fluorite |
| 5 | Apatite |
What mineral can be scratched by a knife?
Hardness
| mineral | Mohs hardness | observations on the minerals |
|---|---|---|
| apatite | 5 | scratched with a knife with difficulty |
| orthoclase | 6 | cannot be scratched with a knife, but scratches glass with difficulty |
| quartz | 7 | scratches glass easily |
| topaz | 8 | scratches glass very easily |
What does it mean when a mineral is scratched?
If the surface of the mineral is scratched then it is softer than the material used to scratch it, if not then it is harder.
What is gypsum used in?
Crude gypsum is used as a fluxing agent, fertilizer, filler in paper and textiles, and retarder in portland cement. About three-fourths of the total production is calcined for use as plaster of paris and as building materials in plaster, Keene’s cement, board products, and tiles and blocks.
What is the hardness of gypsum?
MOHS’ SCALE OF HARDNESS
| Mineral | Hardness | |
|---|---|---|
| Apatite | 5 | Durango, Mexico. Crystal is 7.5 cm. tall. Seaman museum specimen. |
| Fluorite | 4 | Elmwood mine, Tennessee 2.5 cm. (note phantom) |
| Calcite | 3 | Elmwood Mine, Tennessee 8 cm. (twinned) |
| Gypsum | 2 | Wyoming 12 cm. Note “fishtail” twin on left |
How do you determine the hardness of an unknown mineral?
By using a simple scratch test, you can determine the relative hardness of an unknown mineral. Select a fresh, clean surface on the specimen to be tested. Hold the specimen firmly and attempt to scratch it with the point of an object of known hardness.
What minerals can scratch glass?
Quartz (hardness 7) is harder than glass (5.5), so it will scratch the glass.
How can minerals be identified?
Most minerals can be characterized and classified by their unique physical properties: hardness, luster, color, streak, specific gravity, cleavage, fracture, and tenacity.
Is gypsum a mineral?
gypsum, common sulfate mineral of great commercial importance, composed of hydrated calcium sulfate (CaSO4·2H2O). In well-developed crystals the mineral commonly has been called selenite.
How is the mineral gypsum formed?
Gypsum is calcium sulfate dihydrate (CaSO4 2H2O). It is a natural mineral that occurs in certain types of sedimentary rocks. Gypsum forms when water evaporates in mineral-rich marine soil environments. Over long periods of time, evaporation brings more minerals to the soil surface, eventually forming a solid deposit.
How is hardness measured on the Mohs scale?
Mohs Hardness Scale. A mineral’s hardness is a measure of its relative resistance to scratching, measured by scratching the mineral against another substance of known hardness on the Mohs Hardness Scale. This graphic outlines the index minerals and some common objects that are used to determine a mineral’s hardness.
Instead, common objects are used as tools to perform the hardness test: fingernail (hardness = 2.5) copper penny (hardness = 3) glass plate or steel knife (hardness = 5.5) steel file (hardness = 6.5) Using the above testing tools, you should be able to determine the Mohs Hardness of an unknown mineral to the nearest half number on the scale.
What is the hardest mineral that can scratch?
Diamond is the hardest mineral; no other mineral can scratch a diamond. Quartz is a 7. It can be scratched by topaz, corundum, and diamond. Quartz will scratch minerals that have a lower number on the scale.
What minerals can be scratched by a knife?
Limestone and most shells contain calcite. (Can be scratched by a steel pocket knife or sometimes a copper coin. Will scratch a fingernail, may scratch a copper coin.) Fluorine in fluorite prevents tooth decay. (Can be scratched by a steel pocket knife. Will scratch a fingernail and a copper coin.)