CDG Research Methods & Evidence-Based Practice 2

Question 1

Which spectroscopic technique is primarily used to detect the 415 nm absorption line characteristic of Cape series diamonds?

Accepted Answer

UV-Vis absorption spectroscopy

Answer

UV-Vis absorption spectroscopy detects the N3 defect center responsible for the 415 nm absorption line that defines the Cape series.

Question 2

FTIR spectroscopy is most valuable in diamond research for identifying:

Accepted Answer

Nitrogen aggregation states (Type Ia, Ib, IIa, IIb)

Answer

FTIR spectroscopy reveals the infrared absorption patterns of nitrogen defects, allowing researchers to classify diamond types and detect treatments.

Question 3

Raman spectroscopy confirms diamond identity by detecting a characteristic first-order phonon peak at approximately:

Accepted Answer

1332 cm⁻¹

Answer

The sp³-bonded carbon lattice of diamond produces a sharp, characteristic Raman peak at 1332 cm⁻¹, distinguishing it from graphite or simulants.

Question 4

In photoluminescence (PL) spectroscopy research, the H3 center in diamond is associated with:

Accepted Answer

A vacancy-nitrogen complex produced by irradiation and annealing

Answer

The H3 center (vacancy + two nitrogen atoms) is a key PL feature created when irradiated diamonds are subsequently annealed, signaling treatment.

Question 5

The DiamondView instrument aids researchers in distinguishing natural from synthetic diamonds primarily by:

Accepted Answer

Imaging fluorescence and phosphorescence patterns under short-wave UV to reveal growth structure

Answer

DiamondView uses intense short-wave UV to reveal growth patterns—such as CVD columnar banding or HPHT cuboctahedral sectors—invisible under standard gemological examination.

(CDG) Certified Diamond Grader Practice Test

(CDG) Certified Diamond Grader Practice Test

CDG Research Methods & Evidence-Based Practice 2