Mike, tell her to beware of synthetic alexandrite which is sometimes sold as "Russian" because it's made I Russia. A few unscrupulous sellers don't make a distinction between natural and synthetic Russian stones in their sales pitches. The synthetic alex that is virtually chemically identical to the genuine chrysoberyl variety was first made in the U.S. and now is made in many places, sometimes for use in lasers.
Any large alex is suspect unless the price is also huge, and I mean HUGE -- the market was saturated in the early part of the last century with a type of man-made corundum that shows a color change due to doping with vanadium. While such stones show strong color change, it's not the alexandrite green-to-reddish change but more of an amethyst to pinkish color . A simple refraction test distinguishes them. If you know what colors to look for you can do it by eye alone. Just because an "alexandrite" is old doesn't mean it's not a corundum simulant -- they were first made in the 1890s.
Simulants of that kind are commonly sold as genuine alex in tourist destinations like Mexico, Alexandria, Egypt; and elsewhere.