These are tumbled snowflake obsidian crystals. 

Healing Properties of Snowflake Obsidian 

• Balances the mind, body, and soul
• Purifies The Mind
• Combats physical, emotional, and mental attacks
• Helps draw emotions/imbalances to the surface to examine and release them
• Removes negativity from a space or person with ease
• Excellent stone for past life work
• Heals and releases energy blockages
• It is one of the earliest known stones to be used for scrying
• Known to many as a cornerstone to contemplation
• Triggers visions and dreams revealing particularly difficult facets of one's life
• Gives a torrent of insights into self-perfection
• Helps one generate stability in times of uncertainty
• Place between the thumb and index finger to strike a balance in the mind and body
• Dismisses doubts and fears to bring about a new perception of optimism