Optical Properties MCQs

 

Optical Properties

14 questions · Four options each

1. How does the chapter describe color in relation to a gem’s optical properties?

Color is the only optical property
Color is unrelated to light
Color is one of several optical properties that depend on light
Color is determined only by the stone’s size

2. What largely determines a gem’s color, according to the book?

The way it absorbs light
Its weight in air
The number of crystal faces
The type of jewelry setting

3. What instrument does the book say can reveal a gem’s absorption-spectrum “fingerprint”?

A refractometer
A microscope
A polariscope
A spectroscope

4. What gives allochromatic gems their color?

Elements that are always essential to their composition
Trace elements or other impurities
Light reflected from a polished surface only
Their crystal faces absorbing no light

5. What does the book say about pure corundum?

It is always red
It is always blue
It is colorless
It is always green

6. Why does the book say peridot is green?

Its color comes from iron, an essential constituent
It absorbs every color except red
It contains layers of pearl
It is colored by a polished surface

7. Which gem is highlighted as an example of multicoloring?

Corundum
Peridot
Ruby
Tourmaline

8. What does “pleochroic” mean in the chapter?

A gem shows a play of color from internal reflection
A gem shows different colors or shades from different viewing directions
A gem has no crystal structure
A gem reflects light like a mirror

9. What does refractive index (RI) measure, as described in the chapter?

The gem’s resistance to scratching
Its number of colors
The amount of refraction within the gem
Its reflection from internal inclusions only

10. What observation distinguishes singly refractive minerals in the chapter’s refractometer example?

They show a single shadow edge
They show two shadow edges
They show no reflected light
They split into spectral colors

11. What determines a gemstone’s luster?

How light passes through its center
Its specific gravity
The number of its crystal axes
How light is reflected from its surface

12. Which material does the chapter associate with metallic luster?

Turquoise
Pyrite
Amber
Moonstone feldspar

13. What causes interference effects in gemstones, according to the chapter?

Reflection of light from structures inside the gemstone
Scratches on the outside surface
The gemstone’s weight in water
The number of Mohs scale points

14. According to the chapter, what can produce a cat’s-eye effect in a cabochon-cut stone?

A metallic surface polish
A single crystal face absorbing white light
Light reflected from internal features such as parallel fibers
A change in specific gravity