Show britons witness sparkle e of jewels on a screen london the sparkle of d da a monds emeralds and other gems was caught on a screen to ex plain to guests at a meeting held by the royal institution the science behind the fire of a jewel in a darkened room professor gordon directed a narrow beam of light on a succession of brilliant stones and epla explained ined how by cutting the beam was PI 11 t ip L P on reflection ins dp de tl e z one to form a pattern of many 0 ored stars on the each stone colored the pattern according to its natural hue but each of the outer stars of tl e pat tern had the appearance of a ram rain bow in brief the it was as explained a gem little used be cause of its softness had the al power or producing rainbows in pairs an emerald cut in the trad t onal manner gave a pattern of stars tars in the form of a cross in contrast with the random splendor of a bril hant cut diamond in the latter type of cut which science has been able to exola n but not improve the stone has as many as 58 53 facets |