Phonolite

Rock

Also called Clinkstone

About it

Fine-grained volcanic rock rich in feldspar and nepheline with no quartz; thin slabs ring when struck, hence its Greek name, sounding stone. Devils Tower in Wyoming is phonolite porphyry.

Type
Rock (igneous)
Group
Igneous (volcanic)
Specific gravity
2.45–2.7
Lustre
dull
Colours
grey, greenish grey, tan, dark green
Transparency
opaque

Typical values: real specimens vary. For more, see mindat.org.