Dims: 3.62x3.04x2.04" (9.19x7.71x5.18cm)
Wt: 9.43oz (267g)
Siskiyou, California, USA
Like other cristobalite specimens from this location, this one has white cristobalite crystals lining cavities in black obsidian. There is a radial growth pattern, and the mineral does not fill the cavities. A loupe reveals the presence of at least three other minerals: tiny fingers of dull white translucent something (I suspect quartz or another silicon oxide), a dusting of tiny black crystals (too small to identify), and some orange or brown blades that look like wulfenite.