Oracle-Violet Opal, a violet slow opal. This opal is a striking glass that produces a range of misty opal violet tones. It easily resets to transparent pale violet, step one of the striking process. After resetting, allow it to cool to a faint opalescence. O-V-O is slower than our regular Oracle-Opal, and may require a cooler flame to strike. Longer annealing times or higher annealing temperatures can develop more opacity. We anneal at 920°F for two hours or more.