Kristen - your friend is right. The Lighthouse lens cut is a
proprietary cut belonging to Strellman’s - a company in Washington
state I beleive. It was inspired by the Fresnel lens used to amplify
the light emitted by a lighthouse - (tech workers in the theater see
another application of the Fresnel [pronounced Fruh’-nell] lens in
spotlights) Strellmens only does the cut in synthetics because it
wastes so much of the rough in the cutting process - thus the
relatively high price for a synthetic stone. When last I dealt with
Strellmans they would not sell the stones loose, only mounted in
their rings, pendants, etc. It is indeed an intriguing cut - fun to
work with and a challege to design a mounting for. Hope this info
answers your questions.
Mike