Choosing Untreated Sapphires
Untreated describes treatment status, while natural describes formation in the earth. Review the individual sapphire's disclosure and any available laboratory evidence. A natural stone is not automatically unheated or untreated.
Color, Clarity and Origin
Compare hue, tone, saturation, transparency, inclusions, cut, weight and dimensions. Fine untreated material can be rare, but rarity and value depend on the individual stone. Color, geographic origin, inclusions or fluorescence alone do not establish the absence of treatment.
How Is Treatment Status Established?
Identifying heat or other treatments can require qualified laboratory examination. Ask which treatments were tested for and what the findings mean. An absent treatment field is not proof that a stone is untreated.
Appearance and Special Effects
Some corundum shows a star-like effect called asterism when appropriately cut. That appearance does not by itself establish natural origin or treatment status. Judge the actual stone and its documentation.
Price and Care
Compare current product prices rather than relying on a fixed premium for untreated stones. Treatment, fractures and setting design can affect care requirements; ask for advice specific to your chosen stone.
Read the gemstone guides or ask for help before choosing a stone or custom design.