incandescent light (including candle light) is heavily tilted to the red end of the spectrum, thus tipping the balance to red. Color-change sapphires colored by the Cr + Fe/Ti chromophores generally change from blue or violetish blue to violet or purple. Those colored by the V chromophore can show a more pronounced change, moving from blue-green to purple. Certain synthetic color-change sapphires have a similar color change to the natural gemstone alexandrite and they are sometimes marketed as "alexandrium" or "synthetic alexandrite". However, the latter term is a misnomer: synthetic color-change sapphires are, technically, not synthetic alexandrites but rather alexandrite simulants. This is because genuine alexandrite is a variety of chrysoberyl: not sapphire, but an entirely different mineral. Large rubies and sapphires Large rubies and sapphires of poor transparency are frequently used with suspect appraisals that vastly overstate their value. This was the case of the "Life and Pride of America Star Sapphire". Circa 1985, Roy Whetstine claimed to have bought the 1905-ct stone for $10 at the Tucson gem show, but a reporter discovered that L.A. Ward of Fallbrook, CA, who appraised it at the price of $1200/ct, had appraised another stone of the exact same weight several years before Whetstine claimed to have found it. Bangkok-based Lotus Gemology maintains an updated listing of world auction records of ruby, sapphire, and spinel. As of November 2019, no sapphire has ever sold at auction for more than $17,295,796. Cause of color Rubies are corundum with a dominant red body color. This is generally caused by traces of chromium (Cr3+) substituting for the (Al3+) ion in the corundum structure. The color can be modified by both iron and trapped hole color centers. Unlike localized ("intra-atomic") absorption of light, which causes color for chromium and vanadium impurities, blue color in sapphires comes from intervalence charge transfer, which is the transfer of an electron from one transition-metal ion to another via the conduction or valence band. The iron can take the form Fe2+ or Fe3+, while titanium generally takes the form Ti4+. If Fe2+ and Ti4+ ions are substituted for Al3+, localized areas of charge imbalance are created. An electron transfer from Fe2+ and Ti4+ can cause a change in the valence state of both. Because of the valence change, there is a specific change in energy for the electron, and electromagnetic energy is absorbed. The wavelength of the energy absorbed corresponds to