Assignment 18 - Diamond Simulants

Question 1

What is the difference between natural diamonds, lab-grown diamonds and diamond simulants?

Answer 1

Natural and lab-grown diamonds are chemically similar.

Simulants are a different material that looks similar. I can be lab-grown or natural.

Question 2

Why are simulants so popular?

Answer 2

They can be produced at almost any size at much lower costs.

Question 3

What diamond attributes do simulants try to mimic?

Answer 3

• Optical properties (Fire, Brightness, Scintilation)
• Physical properties (Thermal conductivity, hardness)
• Finish (Polish, Edges, Naturals)
• Other (e.g. Fluorescence)

Question 4

Any material that is not natural diamond or lab-grown diamond, but imitates a diamond’s appearance and is used in its place.

Answer 4

Diamond simulant

Question 5

What materials have been used to mimic diamonds?

Answer 5

• Glass and Foilback (ancient)
• Synthetic Sapphire (1990)
• Synthetic Spinel (1990)
• Zircon (early 20th century)
• Synth. Rutile (1948)
• Strontium Titanate (1953)
• YAG (1960)
• GGG (1960)
• Synth. CZ (1970 - today)
• Synth. Moissanite (1990 - today)

Question 6

How do the properties of simulants differ from those of diamonds?

Answer 6

Each simulant has slightly different properties (RI, Fire, Heft) than diamond.

Question 7

What diamond simulants are the most convincing and common?

Answer 7

Synth. CZ and Synth. Moissanite

Question 8

Glass imitation gemstones and diamonds

Answer 8

Paste

Question 9

A gemstone or simulant with a thin metallic foil or mirroring film applied to its pavilion.

Answer 9

Foilback

Question 10

A trade term used to describe diamond imitations made of glass or plastic with or without foilback

Answer 10

Rhinestone

Question 11

How heavy an object feels in relation to its size

Answer 11

Heft

Question 12

What instruments aid in the detection of simulants?

Answer 12

• Diamond tester (thermal or electrical)
• Refractometer (optical)
• Doubling
• Dispersion
• Read-through
• Pavilion flash
• Heft / SG
• Bruted Girdle (old diamonds)
• Inclusions (Gas bubbles & natural)

Question 13

Surface appearance with slightly less sharp reflections than adamantine

Answer 13

Subadamantine

Question 14

Glass-like surface appearance

Answer 14

Vitreous

Question 15

What is the place of simulants in the diamond industry?

Answer 15

They are an alternative product for a different budget, if properly disclosed.

Question 16

What are the common trade names for simulants?

Answer 16

Various names that use a word similar to diamond or even called “hybrid diamond”

Question 17

What issues can arise when buying and selling simulants?

Answer 17

Mistakes, deception, false advertisement.

Question 18

What was one of the first assembled simulants in jewelry?

Answer 18

Garnet-and-glass doublet

Question 19

What indicates coating?

Answer 19

Facet junctions and oily or iridescent facets under magnification.

Question 20

What diamond simulant shows noticeable doubling and strong fire?

Answer 20

• Synth. Rutile
• Synth Moissanite

Question 21

Where can two materials be bonded to create a doublet?

Answer 21

Near the girdle

Question 22

What diamond property enables a diamond probe to separate most simulants from diamond?

Answer 22

Heat conductivity

Question 23

Why do some diamond simulants display “read-through”?

Answer 23

Large critical angles

Question 24

What was a popular simulant in the 1990s?

Answer 24

Natural and synth. Sapphire