What is the Logan Sapphire?
By Jared James · Last updated 21 May 2026
Definition
The Logan Sapphire is one of the largest faceted gem-quality blue sapphires in the world, weighing 422.99 carats and displaying a rich, cornflower to deep blue colour. It was found in Sri Lanka, historically one of the world's most important sapphire sources, and is set as the centrepiece of a brooch surrounded by twenty diamonds. Mrs John A. Logan donated it to the Smithsonian Institution in Washington, D.C., where it is displayed as part of the National Gem Collection alongside the Hope Diamond.
Frequently asked questions
- Where is the Logan Sapphire now?
- The Logan Sapphire is on display at the National Museum of Natural History in Washington, D.C., part of the Smithsonian Institution's National Gem Collection. It sits near the famous Hope Diamond and can be viewed by the public.
- How does the Logan Sapphire compare to other famous sapphires?
- At 422.99 carats it is one of the largest faceted blue sapphires known, though the Star of India, also at the Smithsonian, is larger at 563 carats but is a cabochon star sapphire rather than a faceted stone. The Logan is notable for its exceptional colour and transparency for a stone of its size.
- Where was the Logan Sapphire found?
- It was mined in Sri Lanka, known historically as Ceylon, which has been one of the world's premier sapphire sources for thousands of years and still produces some of the finest blue sapphires available.
Designing a ring
Talk through logan sapphire with us
Tell us what you have in mind, even if it is only a budget and a piece of jewellery type, and we will help you weigh up the options. We reply to every enquiry, usually within one business day.
Contact the studio