CGC Gemstone Treatments & Enhancements Flashcards

What is the most common treatment applied to blue sapphires to improve their color?

Answer: Heat treatment

Heat treatment is the most common and widely accepted treatment for sapphires, used to improve color and clarity by dissolving rutile silk and enhancing hue.

Which gemstone treatment involves filling surface-reaching fractures with lead glass to improve apparent clarity?

Answer: Fracture filling

Fracture filling uses lead glass or other materials injected into surface fractures to reduce their visibility and improve a stone's apparent clarity.

What disclosure is required by U.S. Federal Trade Commission (FTC) guidelines when selling a treated gemstone?

Answer: Material treatment information must be disclosed prior to sale

FTC guidelines require that sellers disclose any material treatments that affect value or require special care, so buyers can make informed purchasing decisions.

Which organization's laboratory is considered the gold standard for detecting gemstone treatments in the U.S.?

Answer: GIA

GIA's laboratory is widely regarded as the gold standard for gemstone treatment detection due to its rigorous research, equipment, and unbiased reporting.

What type of treatment is commonly used on emeralds to mask surface fractures and improve clarity?

Answer: Fracture filling with oil or resin

Emeralds are commonly fracture-filled with cedar oil, synthetic resins, or epoxies to mask surface fractures, a practice so common it is considered standard in the trade.

What is 'lattice diffusion' treatment in sapphires involving beryllium?

Answer: A heat process that drives beryllium into the stone to create or intensify color

Beryllium lattice diffusion involves heating sapphires with beryllium present, which diffuses into the crystal lattice to produce or intensify colors, particularly orange and yellow.