Answer:
It can't be fluorite because your fingernail is less on the Mohs scale than fluorite. When an object is less than another object on the Mohs scale it doesn't leave a scratch on the other object. Therefore if your finger leaves a scratch on the material then it has to be less than 2.5 on the Mohs scale. Fluorrite is not less than 2.5 on the Mohs scale so it is impossible that it is that mineral.
Step-by-step explanation: