Sacred geometry is the study of recurring mathematical patterns — Fibonacci spirals, golden ratio, flower of life, Metatron's cube, Sri Yantra — that appear in nature and in religious symbolism across unrelated cultures. This article explains why these forms are believed to carry protective vibration: they encode the same proportions found in DNA, galaxies, and seashells, creating resonance with natural order. Covers specific geometric talismans used in jewelry (vesica piscis, hexagram, pentagram, infinity knot) and the philosophical lineage from Pythagoras through Kabbalah to modern crystal grids.