Visible biological fossil traces Opal is a silica gel that solidifies over millions of years giving life to opal, in some cases, the silica embodies fossil biological remains or as in this case, shows the passage of small creatures from millions of years ago, this factor makes this piece very rare! Natural Crystal opal rough Big piece Contraluz Ethiopian Welo Untreated! Multicolors 1 piece ( 36 x 32 x 22 mm ) about 30 grams - 150 cts Contraluz - (the contraluz effect occurs when the light is inserted inside or laterally) - pieces with contraluz effect are rare. the pieces for sale is what you see in photos! Lamp light condition! beautiful colors also sunlight! Wet Piece - Photo wet piece Keep moist 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 ) if you want fast shipping, please contact me immediately after the auction win