Kataranskite (another name is Sirenevit) is a rock of lilac color from light to almost inky saturation. Due to its coloring, it is used as an ornamental stone. Mineralogically, kataranskite is a pseudomorph of sericite and some other minerals after plagioclase.
You can see kataranskite stone for sale and buy it in the Minerals of Russia online store.