Contraluz - (the contraluz effect occurs when light is inserted into or from the side) Pieces with a contraluz effect are rare. Natural Contraluz Crystal opal rough Ethiopian Welo Untreated! Multicolors 1 piece (24 x 18 x 17) mm about 8 grams - 40 cts Lamp light condition! beautiful colors also sunlight! Wet Piece - Photo wet piece Keep moist The properties of Opal bring joy and a sense of happiness, increase the joy of living, stimulate artistic creatività and imagination. Opal acts as a prism within the aura, bringing a full spectrum of Light energy to the system, soothing and clearing the emotional body, and boosting the will to live and the joy of one's earthly existence. It is believed that certain gemstones and minerals have beneficial health and spiritual properties. Catawiki cannot guarantee or be held liable for these suggested attributes which have no scientific evidence. please be careful with the description and measures Standard shipping ( 2-7 days for Italy ) ( 10-20 days for Europe ) ( 15-45 days for rest of the world )