Question 1

How much more is an unheated sapphire worth?

Accepted Answer

There is no fixed figure. The premium depends on colour, size, origin and market demand, and it tends to grow with quality and size. At comparable colour and clarity, an unheated sapphire generally sells for noticeably more than a heated one. A heated stone of excellent colour may still be worth more than an unheated stone of poor colour.

Question 2

Can a sapphire be heated without leaving evidence?

Accepted Answer

Sometimes. High-temperature heating usually alters inclusions in recognisable ways, but low-temperature heating can leave few clear signs, especially in clean stones. Laboratories use magnification and spectroscopy, and detection continues to improve, but conclusions remain opinions. This is why important unheated sapphires are often sold with reports from one or more recognised laboratories.

Question 3

Is an unheated sapphire more durable than a heated one?

Accepted Answer

In general, no. Conventional heating does not reduce the hardness of sapphire, which remains 9 on the Mohs scale, and heated stones wear well. Durability concerns arise with other treatments, such as glass-filled fractures in low-grade material. The price difference between heated and unheated stones reflects rarity, not a difference in how they wear.

Question 4

Which lab report is best for an unheated sapphire?

Accepted Answer

GRS, SSEF, Gübelin and GIA are among the laboratories most widely accepted in the international trade for treatment and origin reports. Preferences vary by market and by buyer. For higher-value stones, a report from one of these labs is usually expected, and some buyers prefer two reports from different laboratories for added confidence.

Unheated Sapphires