A coloured gemstone engagement ring can be a beautiful, lasting choice, but only if the stone, the setting and the way you wear it are considered together. GIA explains that durability is not only hardness. Gemologists also look at toughness and stability, which is how a stone copes with heat, light and household chemicals.
Start with the stone, not only the colour
We can source a wide range of gemstones, including specialist cuts, and we will not begin making until you have approved the stone and the design in writing. Before that approval, we look at the species of the gem, any treatment noted on the report, and whether the setting will protect the places that chip or scratch first.
GIA uses the Mohs scale to describe hardness, which is resistance to scratches, but it also warns that the steps on that scale are not evenly spaced. Diamond is 10, and it is many times harder than corundum, even though the numbers sit next to each other. Toughness is resistance to breaking or chipping. Stability is how the stone, and any treatment in it, responds to heat, light and chemicals.
| Gem, as GIA describes it | Mohs hardness | What that means for a ring |
|---|---|---|
| Ruby and sapphire (corundum) | 9 | GIA says excellent toughness, no cleavage, and a great choice for rings subject to daily wear |
| Emerald | 7.5 to 8 | GIA says fair to good toughness, and that it requires more care in wearing than ruby or sapphire |
| Diamond, for comparison | 10 | Harder than the gems above, but a hard blow can still chip any diamond |
Those figures are a starting point, not a rule that every sapphire is automatically right, or that every emerald is automatically wrong. Treatments matter. GIA notes that untreated and heat treated ruby and sapphire are very durable, while fracture filled or dyed stones can be damaged by even mild acids such as lemon juice. For emerald, GIA notes that some estimates state that 90 percent or more are fracture filled, and that ultrasonic or steam cleaning is risky for that reason.
Let the setting protect the stone
A bezel or a lower, more enclosed mount can shield a girdle or a corner. Claws can also be designed to cover vulnerable points. Our note on whether sapphires and emeralds are durable enough for daily wear looks at those two gems in more detail. The same questions apply to other species: how the stone will be worn, and how it will be cleaned.
We work by video consultation and message. Once the stone and the CAD are approved in writing, a 70 percent deposit starts the making, which takes 5 to 6 weeks, and the ring is UK hallmarked before it is sent by insured, tracked FedEx.
If you would like help reading a report or choosing a setting, see our guide to caring for coloured gemstone jewellery, or contact us to talk through the stone in front of you.
Frequently asked questions
What should you check before commissioning a coloured gemstone engagement ring?
Start with the species of the stone, how it will be worn, and what the report says about treatments. Hardness, toughness and stability all matter, and GIA treats those as separate parts of durability.
Are sapphires and rubies suitable for daily wear?
GIA says corundum, which includes ruby and sapphire, is 9 on the Mohs scale, has excellent toughness and no cleavage, and is a great choice for rings and other mountings subject to daily wear. Treatments can change how much care a particular stone needs.
Do emeralds need more care than sapphires?
Yes, in general. GIA gives emerald 7.5 to 8 on the Mohs scale and fair to good toughness, and says it requires more care in wearing than ruby or sapphire. Many emeralds are fracture filled, which also affects cleaning.
When does making begin?
Nothing is made until you have approved the design and the stone in writing. A 70 percent deposit is paid at that point, and making time is then 5 to 6 weeks.