Many of these definitions can be defined in one sentence. Try to recognize how many of these terms affect one another and if you notice that some are the exact same definition, combine them under a heading!

 

Define and provide a diagram where appropriate

Angle of reflection

Reflection

Incident Ray

Ordinary Ray

Extraordinary Ray

Normal Ray

Refraction

Refractive Index

Sine

Isometric

Isotropic

Single Refraction (what would you see)

Double Refraction (what would you see)

Birefringence

Anisotropic

Total Internal Reflection

Critical Angle

Optic Axes

Uniaxial (include explanation of the optic axes)

Biaxial (include explanation of the optic axes)

Alpha Ray

Beta Ray

Gamma Ray

Uniaxial positive (optic sign)

Uniaxial negative

Biaxial positive

Biaxial negative

Lustre

Frenel’s Reflectivity Equation

Reflectance Meter

Becke Line Method

‘Direct Method’

Brewster Angle of Polarization

Diffraction

 

1. What are the 2 laws of reflection?
2. What are the 2 laws of refraction?
3. Describe and diagram the behavior of light with regards to refraction and reflection
4. Explain the difference between using a sodium light and white light
5. Explain the relationship between critical angle and RI
6. Draw and label a Refractometer and map the path of light within it
7. Summarize into brief but detailed steps pg 88-90
8. Summarize the Distant Vision Method into brief but detailed steps
9. With the aid of sketches describe the principle of total internal reflection and show how it is used in a Total Internal Reflection Refractometer
10. Why is it necessary to use contact fluid on the Refractometer and what factors limit the refractometers range?
11. Briefly explain the use of immersion to determine RI
12. Draw a diagram explaining the happenings of light within diamond and quartz
13. You have a necklace containing several colorless transparent facetted stones, some of which are diamonds.  Using a reflectance meter, describe the results you would expect to get.  List the advantages and disadvantages of using this instrument.
14. Briefly explain the relationship between dispersion and RI
15. Which crystal systems are Uniaxial, biaxial or isotropic?
16. You are offered for sale a ring set with four worn and damaged gems consisting of one pink, one red and 2 different green stones.  You obtain indistinct refractive index readings at about 1.63 for the pink, 1.76 for the red, 1.67 for one of the green stones; you obtain no reading for the other green stone. Discuss the possible identities of these four gems and describe how you might be able to confirm their identities. Draw conclusions as to why might you not be able to get a reading from the green stone? Justify all your hypotheses!

 

According to GAGTL we are required to have these memorized for our examinations

Create a quick reference chart, organizing by RI’s in ascending order: (look at the chart at back of Read to make this quick!) You’ll need this chart for the quiz!

Contact Fluid

Glass prism

Amber

Coral

Ivory

Beryl

Chrysoberyl

Corundum

Diamond

All the garnets

Hessonite

The Jades

Opal

Peridot

Quartz

Spinel

Synthetic Spinel

Topaz

Tourmaline

Zircon

Apatite

Feldspars

Iolite

Tanzanite

Andalusite

Kyanite

Dioptase

Glass

Plastic

Scapolite

Sinhalite

Spodumene

Jet

Synthetic materials that differ from their natural counterpart

 

For the quiz, please be prepared to know the biggies (corundum, beryl, diamond etc)

Feedback fr/ the British surrounding our knowing the Refractometer:

People forget or incorrectly label diagrams, don’t know material of prism, people forget to mention necessity of flat surface of gem, what birefringence is EXACTLY, not mentioning taking readings to 3 places,