These are medium sized, high grade Snowflake Obsidian Tumbled Stones.
These Tumbles are priced per single stone.
The average size & weight of these stones are:
30mm x 20mm x 20mm. 16g
Snowflake obsidian is a type of black obsidian with white or grayish spots. These spots are called spherulites, and they are composed of needle-shaped cristobalite, a type of quartz.
Obsidian itself is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth.