The mark on the forehead of Hindus

The Holy Ash is very closely associated with Lord shiva. As the God appeared as the column of fire, It was adorned by the Ash from that fire. Even today for the shiva lingam which resembles the infinite column of flame (the Lord), is anointed with this Holy Ash in specific that symbolizes this associa that symbolizes this association. Having closely associated with the Lord the Holy Ash is of very great significance for the shaivites. Here are a few samples from that great glory.

Holy Ash - An Introduction

Making and Glory of Holy Ash from periya purANam

Holy Ash - Some Information

The application of Holy Ash (bhasma dhAraNa vidhi)

Holy Ash padhikam of thirunyAnachamban^dhar