Ceylon sapphire is not simply "sapphire from Sri Lanka". The island's geology produces a particular character of colour, and knowing what to look for makes the difference between a stone you love and one you regret.
What makes Ceylon material different
Sri Lankan corundum typically has lower iron content than Australian, Thai or African material. Iron makes a sapphire darker and greyer. Low iron is why Ceylon blues often show a slight violet undertone and why they stay bright under indoor light instead of going flat.
That violet undertone is not a flaw. It is the signature of the origin.
Which blue
Trade descriptions for blue sapphire run roughly like this, from least to most valuable:
- Light blue — pale, often watery. Affordable and easy to wear.
- Cornflower — the classic mid blue, neither dark nor light, with good saturation. The sweet spot for most buyers.
- Royal blue — deeper and more saturated, with a slight violet. The top of the commercial range.
- Velvet blue — very deep, almost navy, with the colour held inside the stone rather than reflecting off it. Rare and expensive.
Avoid stones that are grey rather than blue. Greyness is caused by iron and it cannot be cut or set away.
Colour zoning
Many Ceylon sapphires have uneven colour — a darker band through the middle, or a pale edge. A good cutter orients the stone so the strongest colour sits where you look at it. Look at the stone from directly above, not from the side, because that is how it will be seen when set.
Cut
Oval and cushion cuts hold colour best. Round brilliants are brighter but lose more weight, so they cost more per carat for the same colour. Emerald cuts show colour beautifully but reveal any weakness in saturation immediately.
Unheated versus heated
Unheated blue sapphire of good colour is genuinely rare and priced accordingly. Heated stones of the same appearance cost a fraction. Both are real sapphires, both are durable, and both will last a lifetime. Buy unheated if you want the rarity; buy heated if you want the look.
What to ask
Ask for the treatment status, the exact dimensions in millimetres, and a photograph in daylight. If a seller cannot or will not answer those three questions, buy elsewhere.