Zoisite is a Calcium Aluminum Silicate that belongs to the Epidote group of minerals. When it is found transparent, it is formed in to gemstones while translucent-to-opaque material is usually carved into sculptural works. The latter sometimes has Ruby Crystals which are completely opaque and unsuitable as gemstones, but are well colored and contrast strikingly against the green matrix of the Zoisite. Zoisite may be green, blue, brown, pink, yellow, gray or colorless.
Ruby is a light pink to blood red gemstone which is a variety of the mineral Corundum. The common red color is caused by the element Chromium. It is considered on of the four precious stones including Sapphire, Emerald, and Diamond. The price is primarily determined by color, clarity, cut and carat.