No Heat Sapphire Engagement Ring Vintage 1950'sThis no heat sapphire engagement ring is a Vintage 1950s era piece and has a 3. 09 carat oval sapphire as its center stone. The sapphire has not been heat treated and is an exceptionally rare variety of sapphire which exhibits the unique ability to change color when viewed under different light sources. It shifts from blue under natural daylight to a violet purple under incandescent light. This ring has a lovely scroll pattern in the metal on the