How to buy a sapphire

Diamond grading is a rigorous, standardised system built around the absence of colour. Sapphire has no equivalent. There is no universal grading scale, no agreed vocabulary, and no substitute for looking at the stone. What follows is the order of priority that experienced buyers actually use.

1. Colour — this is 60–70% of the price

Colour breaks into three separate things, and people routinely confuse them:

• Hue — the colour itself, including any secondary. “Violetish blue” is a hue.
• Tone — how light or dark, from pale to nearly black.
• Saturation — how pure and intense, versus greyed out or brownish.

Saturation is what you pay for. A vividly saturated stone in a medium tone will always outprice a darker stone of the same hue. A stone that is very dark reads as black in anything but direct light; a stone that is very pale reads as washed out. The money sits in the middle, with as much saturation as possible.

This is why lot HR19 — a 2.55 ct pink — carries the same price as a blue nearly twice its weight. It is not weight. It is saturation.

2. Cut — worth more than people think

Coloured stones are cut to retain weight, because they are sold by weight. That means the cutting is frequently compromised, and it shows in two ways worth checking:

• Windowing — a pale, washed-out patch through the centre where light passes straight through instead of reflecting back. Tilt the stone: if a see-through area opens up, the pavilion is too shallow.
• Extinction — dead black zones that never light up. Some is normal; a lot means the stone is cut too deep or is too dark.

A well-cut stone of modest colour will often outperform a better-coloured stone that has been cut badly. Cut is the most under-rated factor in coloured stones.

3. Clarity — relax

Sapphire is a Type II gemstone: inclusions are expected and normal. The diamond standard of flawlessness does not apply and chasing it is a good way to overpay.

The only questions that matter:

• Can you see anything with the unaided eye at normal distance? If not, it is eye-clean, and that is the standard that counts.
• Is there anything that threatens durability — a fracture reaching the surface, a large inclusion near the girdle where it could be knocked?

Everything else is a fingerprint. Some inclusions are actively good news: undisturbed silk is evidence a stone has never been heated.

4. Carat — last, and here is why

Price per carat rises in steps, not smoothly, and the steps land at round numbers: 1.00, 2.00, 3.00, 5.00. A 2.95 carat stone can cost meaningfully less per carat than a 3.01, and nobody will ever know the difference on your hand.

Buying just under a threshold is the single easiest saving available to you. Lot HR4 at 2.95 ct sits deliberately on the right side of that line.

A practical order of operations

1. Set a budget, and decide whether unheated matters to you. That decision alone moves the budget two to four times.
2. Pick your colour and your minimum size.
3. Ask for photographs and video in more than one light. Video is far more honest than a still.
4. Ask directly: heated or unheated, and any other treatment? Get it in writing.
5. For anything significant, get an independent laboratory report before you commit.
6. Check the return terms before paying, not after.

Questions worth asking any seller

• What treatments has this stone had, specifically?
• Where is it from, and can that be certified?
• Can I see it in daylight and in indoor light, on video?
• What are your return terms, and how long do I have?
• Will you send it to a laboratory of my choosing before I pay?

A seller who is comfortable with all five is a seller worth buying from. Ask us these.