From the studio · Stones, plainly
How to read a stone passport
The short answer: A stone passport is the paper that says exactly what you bought: species, origin, weight, measurements, cut, treatment, and who graded it. Anything a seller will not print on that page is a thing they would rather you did not ask about.
Line one, the species
Sapphire, emerald, spinel, tourmaline. Then whether it is natural or laboratory grown. That word is never abbreviated on our passports and never set smaller than the rest.
Line two, the origin
A country at minimum, a region or a mine where we know it. For grown stones, the method and the reactor location. If we cannot verify a claim, we write the claim and who made it, rather than repeating it as fact.
Line three, treatment
Heat, oil, resin, irradiation, diffusion, or none. Almost all sapphire on earth is heated and that is fine. What is not fine is a passport that leaves it blank. Untreated is a claim that costs money, so it should be a claim someone signed.
The measurements
Millimeters matter more than carats. Two 1.00 carat stones can differ by a full millimeter across the top, and the millimeter is what you see on the hand.