Obsidian (pronounced ub-SIH-dee-in) is a natural glass that forms from volcanic activity. The gemstone is made of the same minerals as granite, but cooled so quickly that the minerals did not have time to crystallize. Some inclusions can be bubbles or crystals, creating random patterns, such as snowflake patterns. Over a long period of time, obsidian can gradually change from glass to rock. This is known as "devitrification." The silica molecules in the volcanic glass slowly rearrange into organized crystal patterns such as the "snowflakes" of quartz crystals that are found in snowflake obsidian. Usually black or dark gray with light gray patches, semiprecious snowflake obsidian beads are believed to assist with clarity and logic.
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