This is an exceptionally fine prismatic crystal of Diaspore from the world-famous gemstone source at the Diaspore gem mine in the Izmir Province of Turkey. It is a prime example of the gem crystals the locality is known for historically, although now the public is being trained to refer to this as a new gem species, "Sultanite," at much higher valuations than the boring-sounding diaspore name might indicate. THIS crystal actually is literally gem rough, and could cut some major stones! This glassy Diaspore crystal is transparent, perfectly formed and lightly striated parallel to its length, which gives nice surface features. Importantly, it has a razor sharp pyramidal termination. The crystal exhibits a discernible alexandrite-style color-change effect, varying from a pale rose-pink to light olive green between sunlight and LED lighting! These are classic, rare and difficult to obtain in this quality as there was a lapse in production here for decades and then renewed recent mining is for gemstone material. It has produced some beautiful crystals recently but only as a byproduct of gem mining, and through the careful intervention of a limited number of people there with access to save the crystals from being chopped to pieces for the emerging, growing market in gemstone Sultanite for the masses. It is nearly perfect, but for a one insignificant tiny corner restoration on one edge only.The mass of this gorgeous crystal is 22.83 grams (which seems shockingly light, given the size - but diaspore has a very low mass per volume and just comes up as lower mass than a comparable sized gem crystal of most other species). This was obtained directly from somebody at the source who was lucky enough to be there when a pocket was hit, and in contact with us. Almost everything else from this pocket was simply cut for the popular market, a shame really.