Are you interested in natural and untreated gemstones?

We specialise in unmounted precious gemstones which are both natural and untreated, each one being sold with a certificate.

A number of treatments were already known and used in antiquity, such as the backing of gems with foil to improve brilliance and colour. But it was the scientific advances of the last couple of centuries that have lead to a variety of more sophisticated techniques being used to alter the appearance of gems.

A majority of recently mined emeralds are 'fissure-filled', which improves their colour and clarity: colourless substances, such as oils, natural or artificial resins are introduced into surface reaching fractures of the stone. Other emeralds are dyed. Most rubies and sapphires mined at present are treated by high temperatures to either lighten, intensify or modify their colour. Pure heat treatment is accepted by the gem industry but often not disclosed, whereas other treatments, such as fissure-filling, dyeing or diffusion treatment – heat is applied with appropriate additives to artificially produce a colour within the surface layer of the stone – are not considered acceptable. As there is at present no universal agreement within the gem industry on how each form of treatment should be disclosed, it is best to invest in certificated gemstones.

If you would like to know more about 'natural v enhanced gemstones', please make an appointment with Robert Ogden. You can contact him on 020 7493 9136 during business hours.