18/09/2026
古柏林實驗室提供矢車菊藍的商業貿易顏色評級。
Cornflower Blue - a new trade colour for Gübelin
We are pleased to announce the introduction of Cornflower Blue beginning January 1st 2027, a trade colour available for Gübelin reports for natural blue sapphires of exceptional colour and visual quality
Inspired by the characteristic blue of the cornflower (Centaurea cyanus), the term cornflower blue has long been used within the gemstone trade, although interpretations of its exact definition vary.
With Cornflower Blue, the Gübelin Gem Lab establishes a stringent and clearly defined set of criteria for this coveted trade colour.
To qualify for Cornflower Blue for Gübelin, a sapphire must meet the following criteria:
• Natural blue sapphire from any geographical origin
• No signs of treatment, including heat or clarity enhancement
• Saturated blue colour with a light to moderate tone, possibly with a gentle hint of violet
• Homogeneous colour distribution
• High level of transparency; a slight velvety appearance caused by subtle light scattering is welcome, though not compulsory
• No eye-visible inclusions and no dark inclusions
• No major windowing or extinction
• Lively colour reflections (when faceted)
The designation Cornflower Blue for Gübelin is independent of geographical origin and is assessed based on the individual visual characteristics and quality of the sapphire. Only a small proportion of blue sapphires are expected to fulfil all required criteria.
From January 2027, qualifying sapphires will be eligible to receive the Cornflower Blue on reports issued by the Gübelin Gem Lab.
Clients who have submitted a sapphire to the Gübelin Gem Lab within the past five years may request a reconsideration of their stone for the Cornflower Blue. For eligible stones, the reconsideration service will be offered at a 75% discount on the applicable service fee.
