Alexandrite Questions & Answers

"It is better to know some of the questions than all of the answers." James Thurber, (1894 - 1961)
1. Is there a difference between "Russian" and "Brazilian" Alexandrite gemstones?
2. What makes natural alexandrite so expensive?
3. What is the difference between chrysoberyl and alexandrite?
4. What is the difference between cat's eye and alexandrite?
5. What causes the cat's-eye effect in chrysoberyl?
6. Are there any other gemstones which change color?