https://gemritual.com/blogs/gemstone-encyclopedia/why-unakite-cannot-be-identified-by-refractive-index-alone-reconciling-a-heterogeneous-rock-with-standard-optical-testing 2026-09-12T13:09:20-07:00 weekly https://cdn.shopify.com/s/files/1/0810/3267/5579/articles/pexels-photo-32489243_cc5e56f2-4ad5-4280-8bf7-b8f349b2d29c.jpg?v=1789243759 Why Unakite Cannot Be Identified by Refractive Index Alone: Reconciling a Heterogeneous Rock with Standard Optical Testing https://gemritual.com/blogs/gemstone-encyclopedia/sugilites-color-direction-why-one-stone-can-look-violet-pink-and-brownish-in-different-crystal-directions 2026-09-12T14:09:18-07:00 weekly https://cdn.shopify.com/s/files/1/0810/3267/5579/articles/pexels-photo-6757423_3fd31ff5-0061-4855-b99e-fd7ff4fd35fb.jpg?v=1789247357 Sugilite's Color Direction: Why One Stone Can Look Violet, Pink, and Brownish in Different Crystal Directions