The isotropic mineral has no pleochroism, and there are no positive or negative relief.
举一反三
- The relief grade of fluorite is : ( ) A: Negative high relief B: Positive low relief C: Positive median relief D: Twinkling
- The relief grade of muscovite is : ( ) A: Negative high relief B: Positive low relief C: Positive median relief D: Twinkling
- The section which is cross to optical axis of anisotropic mineral has no pleochroism and absorption.
- Basic research has: A: Positive externality B: Negative externality C: Both positive externality and negative externality D: Neither positive externality nor negative externality
- Gift-giving both has positive and negative aspects.