Purple sapphire derives its color from a mix of blue (titanium and iron) and red (chromium) dopants. In the flame fusion process, the iron and titanium change valence states, leading to a color difference between the center and the rim of the boule. While this can create a striking effect in a cut gem, the color consistency varies. Conversely, Czochralski-grown purple sapphire avoids this zoning issue through precise control over the growth chamber, resulting in a uniformly colored crystal. Despite its high production costs and lack of optical or industrial applications, this material is primarily supplied due to demand for full sapphire watch cases. This ornamental color, among others, is increasingly being produced to meet the rising demand for CNC-machined full sapphire watch cases.

We received this batch of material from a supplier specializing in watch case materials.