Assessing Diamond Value: The Four C's

Diamond Weight and Measurement

• 1 carat is equal to 0.2 grams
• 100 points in carats are equivalent to 0.5 carats

Diamond Classification

• Small diamonds under 0.20ct are often referred to as "melee"
• A diamond graded as 'D' signifies colorless, meaning it has no detectable color

Fancy Color Grading

• Fancy colors in diamonds are graded using a specific method
• The main factor considered for grading fancy colors is the hue, saturation, and tone of the diamond

Color Grading Challenges

• CZ master stones may be less accurate for estimating the color-group grade due to the presence of fluorescence
• It is not possible to accurately color grade a mounted diamond because the setting can affect the appearance of the diamond

Fancy Colored Diamonds

• Fancy colored diamonds are graded for their intensity, hue, and saturation of color

Fluorescence and Color

• Strong fluorescence can influence the color of a diamond seen in daylight
• The intensity of fluorescence is graded under Long Wave (LWUV) and the main factor considered is the strength of the fluorescence

Clarity Grading

• When using dark-field illumination/edge of the light beam, clarity is primarily graded for inclusions
• A 'feather' in a diamond is a type of inclusion that can affect the stone's clarity
• The highest grade on the GIA Clarity Scale is Flawless (FL)

Clarity Grading with a 10x Loupe

• Clarity is primarily graded from the table view when using a 10x loupe

Non-Lab Testing

• Observations used to determine the ID of a stone in non-lab testing include thermal conductivity, electrical conductivity, and optical properties
• The Thermal conductance probe and Electrical conductance probe are used to conduct tests in non-lab testing
• A Polariscope aids in the testing of diamonds by detecting birefringence and strain patterns
• The Tatami strain pattern indicates a diamond when viewed using a Polariscope

Identifying Synthetic Diamonds

• Crossed polarizing filters can help in identifying synthetic diamonds by detecting their birefringence
• Plastic deformation in diamonds viewed under crossed polars indicates a natural diamond
• Metallic inclusions are observed in HPHT synthetic diamonds
• Clarity treatments involving fracture filling are observed in some diamonds

Laser Inscriptions and Detection

• Laser inscriptions can be identified on diamonds
• The DTC DiamondSure Portable is used to detect diamond authenticity
• The DTC DiamondView determines natural or synthetic diamonds by detecting their optical and spectroscopic properties

Synthetic Diamond Identification

• Distinctive growth patterns are observed in HPHT synthetic diamonds
• Diamonds can be detected based on their growth patterns and fluorescence
• The basis for identifying diamond types using specialized screening equipment is their optical and spectroscopic properties
• The Cathodoluminescence (CL) test assesses the presence of defects in diamonds

Synthetic Moissanite Detection

• The presence of synthetic moissanite can be detected using the DTC DiamondSure Portable

Test your knowledge about assessing the value of a cut diamond according to the four factors known as the 'four C’s': Carat Weight, Colour, Clarity, and Cut quality. Explore how these factors contribute to the overall value of a diamond.