For other uses, see Zechariah. The male given name Zechariah is derived from the Hebrew ×Ö°×Ö·×¨Ö°×Ö¸×, meaning The Lord has remembered.. It has been translated into English in many variant forms and spellings, including Zachariah, Zacharias and Zachary. It was the name of various men in the Bible.
Double Refraction in Minerals Double refraction is the splitting of a single ray of light into two refracted rays when passing through an anisotropic mineral. All anisotropic minerals exhibit double refraction. Double refraction can be practically observed by placing a transparent Calcite (Iceland spar) crystal on a sheet of paper with a black dot on it. When the dot is viewed through the crystal, two dots are seen.
Refraction of light at the interface between two media of different refractive indices, with n2 > n1. Since the phase velocity is lower in the second medium (v2 < v1), the angle of refraction Î¸2 is less than the angle of incidence Î¸1; that is, the ray in the higher-index medium is closer to the normal.