Assignment 18 - Diamond Simulants Flashcards
What is the difference between natural diamonds, lab-grown diamonds and diamond simulants?
Natural and lab-grown diamonds are chemically similar.
Simulants are a different material that looks similar. I can be lab-grown or natural.
Why are simulants so popular?
They can be produced at almost any size at much lower costs.
What diamond attributes do simulants try to mimic?
- Optical properties (Fire, Brightness, Scintilation)
- Physical properties (Thermal conductivity, hardness)
- Finish (Polish, Edges, Naturals)
- Other (e.g. Fluorescence)
Any material that is not natural diamond or lab-grown diamond, but imitates a diamond’s appearance and is used in its place.
Diamond simulant
What materials have been used to mimic diamonds?
- 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)
How do the properties of simulants differ from those of diamonds?
Each simulant has slightly different properties (RI, Fire, Heft) than diamond.
What diamond simulants are the most convincing and common?
Synth. CZ and Synth. Moissanite
Glass imitation gemstones and diamonds
Paste
A gemstone or simulant with a thin metallic foil or mirroring film applied to its pavilion.
Foilback
A trade term used to describe diamond imitations made of glass or plastic with or without foilback
Rhinestone
How heavy an object feels in relation to its size
Heft
What instruments aid in the detection of simulants?
- Diamond tester (thermal or electrical)
- Refractometer (optical)
- Doubling
- Dispersion
- Read-through
- Pavilion flash
- Heft / SG
- Bruted Girdle (old diamonds)
- Inclusions (Gas bubbles & natural)
Surface appearance with slightly less sharp reflections than adamantine
Subadamantine
Glass-like surface appearance
Vitreous
What is the place of simulants in the diamond industry?
They are an alternative product for a different budget, if properly disclosed.
What are the common trade names for simulants?
Various names that use a word similar to diamond or even called “hybrid diamond”
What issues can arise when buying and selling simulants?
Mistakes, deception, false advertisement.
What was one of the first assembled simulants in jewelry?
Garnet-and-glass doublet
What indicates coating?
Facet junctions and oily or iridescent facets under magnification.
What diamond simulant shows noticeable doubling and strong fire?
- Synth. Rutile
- Synth Moissanite
Where can two materials be bonded to create a doublet?
Near the girdle
What diamond property enables a diamond probe to separate most simulants from diamond?
Heat conductivity
Why do some diamond simulants display “read-through”?
Large critical angles
What was a popular simulant in the 1990s?
Natural and synth. Sapphire
