Advanced evidence type 4 - gemstones

Question 1

What are Gemstones?

Answer 1

These are minerals that are cut and polished to be used in jewellery
When they are exposed to short or long wave UV radiation, they emit visible light or fluoresce

phosphorescent - This happens if the luminescence continues after the exposure to UV radiation which is due to impurities and defect in the crystal lattice

Question 2

How do we characterise nanostructures?

Answer 2

Surface microscopy;
Scanning electron
transmission electron
Atomic force

Bulk diffraction;
X-ray power

Question 3

What is X-ray diffraction?

Answer 3

Used to establish the arrangement of atoms within a crystal structure and how they stack together
Use Bragg’s law

Question 4

What can x-ray diffraction determine?

Answer 4

Lattice parameters
Phase composition of the sample
Crystal structure
Crystallite size