Any material that is not diamond or synthetic diamond, but which imitates a diamond’s appearance and is used in its place
Diamond simulant
Two separate pieces of material fused or cemented together to form a single assembled stone
Doublet
Gemstone or simulate with a thin metallic foil or mirroring film applied to its pavilion
Foilback
A foilbacked, colorless, lead-glass diamond imitation
Rhinestone
Process of distinguishing natural minerals and gems from each other as well as from synthetics, simulants, and treated gems
Separation
An instrument that measures thermal conductivity to help separate natural and synthetic diamonds fro most simulants
Thermal tester
Which is the following is a natural gem?
Zircon
Diamond imitations called “paste” are actually
Glass
Diamond simulants
only look like diamonds
The thermal diamond tester helps separate diamond from most simulants because of diamond’s excellent ability to
Conduct heat
Diamond has higher thermal conductivity than almost any simulant. This means it stays cooler longer when exposed to heat, so a diamond feels cooler to the touch than a simulant.
The term “Diamond Simulant”
Refers to a stone that looks like a diamond but has different optical, physical, and chemical properties
Which diamond simulant shows noticeable doubling and strong fire?
Synthetic rutile
- may find in some estate jewelry
- Quite brilliant but not as much as diamond
- Very high dispersion-rainbow colors are obvious
- low hardness–quickly shows signs of wear
- doubly refractive
Which of the following typically has a waxy to granular girdle surface?
Diamond.
The easiest way to separate diamond from synthetic moissanite is by checking for
Doubling
- Introduced in late 1990s
- First developed for industrial use
- slightly yellowish or greenish
- 9 1/4 MOHS scale
- less brilliant than diamond but more fire than diamond and CZ but less fire than synthetic rutile
- Doubly refractive
- Lower SG than diamonds (it’s lighter than diamond)
- Won’t see bearding or naturals around the girdle
- the only simulant that can fool some thermal testers
The easiest way to separate diamond from synthetic cubic zirconia is by checking for
thermal conductivity.
- Entered market in 1970s
- Most commonly used simulant
- SG is heavier than diamond
- Almost as brilliant and lustrious as diamond
- Mohs hardness of 8 1/4
The easiest way to separate diamond from zircon is by checking for
Doubling
- A natural gem
- More brilliant than glass and has medium fire
- Doubly refractive
- Chip and scratch easily
- Heat treatment makes them brittle, so rarely used today
Which of the following properties is higher in GGG than in diamond?
Specific Gravity
- YAG was created n 1960s–lab grown crystals with garnet-nlike cubic crystal structure
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A diamond imitation that’s foilbacked or composed of colorless lead-glass might also be called a
Rhinestone
A stone formed by cementing two separate pieces of material together is called a
Doublet
All diamond simulants rank lower than a diamond in
Hardness
Some diamond simulants display “see-through’ because, compared to diamond, they
Have much larger critical angles
Most have a lower refractive index and larger critical angle than a diamond, leading to light leakage through the pavilion.
What is a diamond’s Specific Graving (SG) rating?
3.52
What is a diamond’s Refractive Index (RI)?
2.417
What are three examples of flame fusion simulants?
- Rubies
- Sapphires
- Spinel
Created in late 1800s. Often found in clas rings and imitation birthstone jewelry
