I am currently the Digital Coach for the City of London and the West, within the London and Midlands Region. My role in a nutshell is to coach our leaders on sustainable banking whilst making the lives our of customers easier.
(There is also genuine color-change sapphire which mimics alexandrite, as well as color-change garnet that can be a real fooler.). The first thing to do is check the refractive index of the stone, since each material has unique optical properties.
Just a quickie here. i have used royal purple before...Ive been using castrol GTX synthetic for the past maybe 5 or 6 changes.. I really have seen no difference in ither really. I can get 5 quarts and a good filter for like 25 bucks on sale..a little better that the 7.99 a quart +tx for royal purple.