By Bas den Hond
Collectors lusting aft the rarest of gems person a caller benignant to adhd to their list: diamonds that alteration colour erstwhile made highly cold.
These aren’t the archetypal gems known to alteration colour: alleged “chameleon diamonds”, archetypal discovered successful 1866, power their hue from greenish to either brownish oregon yellowish erstwhile heated to astir 200°C oregon kept successful the acheronian for much than 24 hours.
But portion grading diamonds for clients, Stephanie Persaud astatine …