Gemstone Origin

The source of a gemstone can have a huge impact on its value. For example:

• Burmese Ruby is more valuable than Thai or African ruby.
• Kashmir, Burmese (Myanmar) or Ceylon (Sri Lanka) Sapphire commands a premium over Australian or African sapphire.
• Colombian Emerald is historically prized, but Zambian emeralds are gaining strong market value.

“Origin is everything in coloured gemstones,” says Matthew. “It’s like the terroir of wine — where it’s from says a lot about its quality.”

Treatment (Heated vs. Unheated)

Unheated or untreated gemstones have become increasingly sought-after by collectors. The natural, untouched state of a gem carries rarity and authenticity that commands premium pricing, even in smaller sizes.

• Unheated sapphire or ruby can fetch significantly more per carat.
• Tsavorite garnet and spessartine garnet are typically unheated, driving collector interest.
• Paraiba tourmaline often holds value due to its unique copper content and rare treatment status.

“We’re seeing a shift towards buyers valuing unheated stones, even if that means accepting smaller sizes or slight inclusions,” says Matthew.
      
Colour and Saturation

The richness of colour — known as saturation — is often more important than size. A vivid, well-saturated gem in a smaller carat weight can far outperform a larger but poorly coloured stone.

“Colour is key,” Matthew says. “Collectors will always choose a vivid one-carat stone over a dull three-carat stone.”

Cut and Shape

Unlike diamonds, coloured gemstones aren’t always cut for ideal proportions. Often, they’re cut to preserve weight or maximise colour. This can affect spread (how big the gem looks) and brilliance.

• Some sapphires may have deep pavilions or off-centre cuts to enhance colour.
• Ruby and sapphire cuts often focus on maximising yield, not symmetry.

“You’ll often see stones cut too deep just to hold more carat weight — but that doesn’t mean they’re better,” Matthew explains. “A well-cut gem will always shine brighter.”