Mohs scale of mineral hardness integrity, they are not considered "scratches" for the determination of a Mohs scale number. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below
The Rocks Crumble The Rocks Crumble The Rocks Crumble is the eighth Jandek album, released as Corwood 0746. It is his third release of 1983, and is the first Jandek album to feature extensive use of drums and electric guitar. It was reissued on CD in 2001. "The Rocks Crumble" marks the beginning of what is often referenced as Corwood's "first electric period," since the majority of the album is played on electric guitar with clattering, earsplitting drums behind it. That said, Jandek eases us into this new phase gently, and its approach echoes the cover, in which an old Slingerland drum set