01
The value factors
Colour, saturation, tone, transparency, clarity, size, cut quality and treatment all interact. A strong colour can be undermined by poor transparency; a clean stone can feel weak if its colour is pale.
Origin confidence and a respected laboratory report may affect buyer confidence, but a report does not make an unattractive stone beautiful.
02
Use market examples carefully
An asking price is not an achieved sale price. Any market comparison should record the date, stone, weight, quality description, treatment information, source and whether the figure was advertised or actually achieved.
This site will publish real examples only when the underlying data can be described honestly.