Other uses Because it is a good electrical insulator and fireproof, it was used to construct early-20th-century electric switchboards and relay controls for large electric motors. Fine slate can also be used as a whetstone to hone knives. Due to its thermal stability and chemical inertness, slate has been used for laboratory bench tops and for billiard table tops.  In 18th- and 19th-century schools, slate was extensively used for blackboards and individual writing slates, for which slate or chalk pencils were used.
Other uses Because it is a good electrical insulator and fireproof, it was used to construct early-20th-century electric switchboards and relay controls for large electric motors. Due to its thermal stability and chemical inertness, slate has been used for laboratory bench tops and for billiard table tops. Fine slate can be used as a whetstone to hone knives. In 18th- and 19th-century schools, slate was extensively used for blackboards and individual writing slates, for which slate or chalk pencils were used.
D
Fine slate can also be used as a whetstone to hone knives.
A
Fine slate can be used as a whetstone to hone knives.