GIA Laboratory Testing & Equipment 3

Question 1

Which GIA instrument is specifically designed to distinguish natural diamonds from HPHT-grown synthetic diamonds based on luminescence?

Accepted Answer

GIA iD100

Answer

The GIA iD100 uses short-wave UV photoluminescence to screen loose diamonds and separate naturals from synthetics for further testing.

Question 2

In the DiamondView instrument, what type of radiation is used to induce fluorescence patterns?

Accepted Answer

Short-wave UV below 230 nm

Answer

The DiamondView uses very short-wave UV radiation (below 230 nm) to induce fluorescence patterns that reveal a diamond's growth structure.

Question 3

A diamond examined under the DiamondView shows a cuboctahedral fluorescence pattern. What does this indicate?

Accepted Answer

HPHT synthetic diamond

Answer

HPHT synthetic diamonds grow in a cuboctahedral pattern, which produces a distinctive cross or hourglass fluorescence pattern in the DiamondView.

Question 4

What characteristic fluorescence pattern does a CVD synthetic diamond typically show under the DiamondView?

Accepted Answer

Layered or striated parallel growth lines

Answer

CVD synthetic diamonds show layered, striated growth patterns reflecting the layer-by-layer deposition process used in chemical vapor deposition.

Question 5

Which piece of equipment measures the electrical conductivity of a stone to differentiate moissanite from diamond?

Accepted Answer

Moissanite tester (electrical tester)

Answer

Dedicated moissanite testers use electrical conductivity because moissanite conducts electricity while diamond (an electrical insulator) does not.

(GIA) Certified Diamonds Gemological Institute of America Practice Test