Lab Grown Emerald, Ruby and Sapphire: A Buying Guide

Colour gemstones have no universal grading standard — which is exactly why they are harder to buy well than diamonds. Diamond has GIA. Moissanite has GRA. Coloured stones have no single accepted scale, so two sellers can both write "AAA" and mean completely different things. Here is what to actually look at for emerald, ruby and sapphire.

What "lab grown" means for colour stones

A lab grown colour stone has the same chemical composition and crystal structure as the mined version. It is not a simulant — not glass, not cubic zirconia, not a coated substitute. It is the same material, grown from a seed in a controlled environment rather than formed underground over millions of years.

The practical difference is inclusion. Mined emerald almost always has "jardin" — internal fractures and inclusions that are part of its identity and also its fragility. Lab grown emerald can be produced clean, or deliberately produced with inclusions to look more like the mined version. Both exist, and sellers should say which.

Emerald: the one that breaks

Emerald is 7.5 to 8 on the Mohs scale, but hardness is not the whole story — emerald is brittle. It has internal fractures that make it vulnerable to impact and to sudden temperature change. A hard knock on a table edge can chip it in a way that would never trouble a sapphire.

What to look for: a saturated bluish-green rather than a yellowish-green (Colombian-type is the reference point), even colour across the stone rather than patchy, and no visible surface-reaching fractures.

Setting advice: a bezel or a protective halo. Prongs at the corners of an emerald cut are the classic failure point. Avoid wearing an emerald ring for gardening, gym, or anything with impact.

Cleaning: warm water and soft brush only. No ultrasonic — the vibration can propagate existing fractures.

Ruby: colour is the whole value

Corundum at 9 on the Mohs scale, so durability is not the issue. Ruby's value is almost entirely colour: a vivid slightly bluish red ("pigeon blood") commands far more than a brownish or purplish red of the same size and clarity.

What to look for: saturation first, then tone. A stone that is too dark reads brown; too light reads pink. Look at it in daylight, not under shop lighting, which flatters red considerably.

Watch for: surface-reaching fractures filled with lead glass, which is common in low-grade ruby and unstable over time. Lab grown ruby does not need filling, which is one of its genuine advantages.

Setting advice: ruby tolerates prongs well. Any setting works.

Sapphire: the most forgiving

Also corundum, 9 on Mohs, and the most practical of the three for daily wear. Blue is the reference colour, but sapphire also occurs in pink, yellow, green, purple, and the rare pink-orange padparadscha.

What to look for: a velvety, evenly saturated blue (Cornflower or Royal blue as reference points), no visible colour zoning (bands of different colour), and no window — a "window" is a washed-out area in the middle of the stone where light passes straight through instead of reflecting back.

Padparadscha is the rarest colour and the one most often misdescribed. A true padparadscha sits between pink and orange, like a lotus petal. Stones sold as padparadscha that are really orange sapphire or pink sapphire are common. Ask for the colour in daylight.

Setting advice: sapphire is the best daily-wear colour stone. Prongs, bezel, halo — all fine.

Cut matters more than people expect

Coloured stones are cut for weight retention far more often than diamonds are, because rough is expensive and uneven. The result is stones with a deep pavilion (dark centre), a shallow pavilion (window), or an off-centre table.

Look at the stone face-up in daylight. If you can see straight through it to your finger, it is windowed and will look flat no matter how good the colour is. If the centre is noticeably darker than the edges, the pavilion is too deep.

A well-cut 6mm stone looks better than a badly cut 7mm one and costs less. This is where the money should go.

What colour stones cost here

Our lab grown colour range starts at $18.50 for a loose stone and runs to several thousand for large certified pieces in solid gold. Median across the colour stone range sits around $90–$150 depending on size and metal.

The pattern is the same as everywhere: the stone is a small part of the price. A 7mm lab grown sapphire loose might be $40; the same stone in an 18K gold halo ring is $900. Metal and labour dominate.

Buying checklist

• Ask for the actual stone's photo, not a stock image. Colour stones vary between pieces far more than moissanite does.
• Ask what certificate comes with it — GRA or IGI for lab grown. A certificate should state colour, clarity and carat, not just "natural-looking".
• Ask whether the stone is treated (filled, heated, diffusion). Lab grown stones generally are not, but ask.
• For pairs or matched sets, ask for stones cut from the same rough so colour matches. Two singles from different batches will not match.
• Check the return policy on colour stones specifically — colour is subjective and photos never fully convey it.

Our lab grown colour stones are cut and set in our Wuzhou workshop. Browse lab grown emerald, lab grown ruby, lab grown sapphire, or the full lab grown gemstone range. Coloured stones from $18.50, 30-day returns, made in 925 silver or solid 9K–18K gold.