This is a 5.24 ct cushion-cut Hackmanite, a variety of Sodalite, certified by GIA. It exhibits a violetish-blue color in normal lighting but is highly reactive to UV light, undergoing a strong color shift.

Once the UV source is removed, it transitions into a deep royal blue, which gradually fades back to its original violetish-blue color over time. This phenomenon is a result of tenebrescence—a rare optical property where a mineral undergoes a reversible color change when exposed to UV radiation.

Additionally, the GIA report mentions Clarity Enhancement, a temporary treatment often used for Hackmanite due to its relatively soft nature. This enhancement is typically achieved by immersing the stone in oil, which can temporarily improve its clarity by filling microscopic surface-reaching fractures. However, this effect is not permanent and can diminish over time.

Note: Certifications from additional labs can be made upon request, with the expenses to be borne by the customer.