Eric says: “Sapphires mined in Montana, USA, fall into two categories, the more common ones extracted from along the banks of the Missouri River which need heat treatment to reveal their bright colours, known as ‘Montana Sapphires’, and the rarer sapphires from the Yogo Gulch in Montana that need no heat treatment to reveal their vivid blue colour and are called ‘Yogo Sapphires’.
This gem is a superb example of the rarer Yogo sapphire, mined at the Yogo Gulch and faceted many years ago; the blue is of medium strong saturation with medium tone, evenly distributed through the gem, without any detracting secondary colours present. The clarity is eye-clean, as shown in the images”.
1.22 carats, round brilliant cut, measuring 6.45mm diameter, 4.20mm in depth, not treated in any way.
Accompanied by an SSEF Gem Report 152030. 9 Feb 2026. See the scan stating “No indications of heating. Origin: Yogo, Montana (USA)”
Eric says: “Sapphires mined in Montana, USA, fall into two categories, the more common ones extracted from along the banks of the Missouri River which need heat treatment to reveal their bright colours, known as ‘Montana Sapphires’, and the rarer sapphires from the Yogo Gulch in Montana that need no heat treatment to reveal their vivid blue colour and are called ‘Yogo Sapphires’.
This gem is a superb example of the rarer Yogo sapphire, mined at the Yogo Gulch and faceted many years ago; the blue is of medium strong saturation with medium tone, evenly distributed through the gem, without any detracting secondary colours present. The clarity is eye-clean, as shown in the images”.
1.22 carats, round brilliant cut, measuring 6.45mm diameter, 4.20mm in depth, not treated in any way.
Accompanied by an SSEF Gem Report 152030. 9 Feb 2026. See the scan stating “No indications of heating. Origin: Yogo, Montana (USA)”
Feel free to WhatsApp me to discuss this sapphire. I can video chat with you to show you the gem and/or book an appointment to see it in Hatton Garden at my place of work.
1.22 carats Yogo Sapphire
