1. Allochromatic minerals may show more than two colours.
a) True
b) False
Explanation: Many non-metallic minerals like quartz, calcite, fluorine, tourmaline etc. may occur in more than two colours depending on the nature of impurities
2. Pseudochromatism occurs due to ___________
a) Reflection
b) Transmittance
c) Refraction
d) Simultaneous reflection and refraction
Explanation: Psuodochromatism is attributed to simultaneous reflection and refraction from the mineral surface due to minute inclusions of impurities in the mineral at different locations.
3. The phenomenon due to which a mineral shows rainbow colours is?
a) Idiochromatism
b) Allochromatism
c) Iridescence
d) Pseudochromatism
Explanation: Some minerals may show rainbow colours either in their interior or on the exterior surface. This is called iridescence.
4. Play of colours is not desirable.
a) True
b) False
Explanation: Due to play of colours, the colours change in rapid succession on rotation and their effect is quite brilliant and appealing to the eye.
5. Colour changing phenomenon which involves oxidation is ____________
a) Tarnish
b) Iridescence
c) Allochromatic
d) Idiochromatic
Explanation: Tarnish nay be described as a phenomenon of change of original colours of mineral to some secondary colours at its surface due its oxidation at the surface
6. Lustre doesn’t depend on?
a) Refractive index mineral
b) Absorption of mineral
c) Transmittance of mineral
d) Nature of reflecting surface
Explanation: Lustre depends on: refractive index of the mineral, absorption capacity of the mineral and nature of reflecting surface
7. Type of shine or lustre associated with lustre of diamond is ___________
a) Adamantine
b) Metallic
c) Pearly
d) Vitreous
Explanation: Adamantine is the other name for shine of diamonds. Very brilliant; the best example is diamond.
8. Streak is an important diagnostic property of ___________
a) Non-coloured minerals
b) Coloured minerals
c) Metallic minerals
d) Non-metallic minerals
Explanation: Streak is an important diagnostic property of many coloured minerals. Simply defined as the colour of the finely powdered mineral as obtained by scratching or rubbing the mineral over rough unglazed porcelain plate.
9. Which mineral gives streak?
a) Coloured and translucent
b) Colourless and opaque
c) Coloured and opaque
d) Coloured and transparent
Explanation: Colourless and transparent minerals will always give a colourless streak that has no significance. The coloured and opaque minerals, especially of ore groups, give typically characteristic streaks quite different from other similarly looking minerals.
10. The mineral which is almost black but gives brown streak is?
a) Magnetite
b) Garnet
c) Hornblende
d) Chromite
Explanation: Chromite and magnetite resemble closely in their other physical properties: both are almost black. These may be at once distinguished by their streaks: brown for chromite and black for magnetite