What temperature do you heat treat sapphires?
Heat treatment is used to improve a sapphire’s color, remove color zoning , and improve clarity. Some heat treatment procedures are relatively mild, involving temperatures of about 400 degrees Celsius for brief periods of time.
Do sapphires need to be heat treated?
Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and value.
What happens when you heat treat a sapphire?
Heat can also change the colors created by other minerals as well. For example, high enough iron content will give a green or yellow color to a sapphire; heating typically causes an iron-rich sapphire to turn a deeper yellow.
What is the difference between heated and unheated sapphires?
By appearance, is there a difference between natural and heat-treated sapphires? Yes, but to a trained eye. Generally speaking, natural no-heat sapphires will have a softer luster and smoother surface appeal. Heated sapphires display a glass-like surface that feels hard and unnatural.
Are unheated sapphires more valuable?
Are natural, no-heat sapphires more rare and valuable? Yes, sapphires that have not undergone any color or clarity enhancement along the supply chain (mine to retail) are rare and therefore more valuable than heated sapphires that are abundant in the market.
How can you tell if a gemstone is heat treated?
Heat treatment is a very risky process as many gems have inclusions that expand at a different rate and cause stress fractures, which then becomes an identifying characteristic of heated gems, particularly sapphire and ruby which can display halos around inclusions within the gem.
Do heat treated sapphires fade?
The color of a heat-treated sapphire will remain permanent and will not change or fade unless the stone undergoes a secondary treatment. This is the reason why heat treatment on sapphires is accepted by most retailers.
How can I test my blue sapphire at home?
Check the gem for air bubbles. Since they are glass, tiny air bubbles remain in them after they form. If you see any bubbles inside of the sapphire then it is not real. Be sure to turn the sapphire over and inspect it from every angle. It’s possible that air bubbles will only be visible from one angle.