Rudra Dhyaana Shloka

हरि सर्वोत्तम । वायु जीवोत्तम | श्री गुरुभ्यो नमः

ध्येयः पंच-मुखो रुद्रः स्फटिक-अमल-कान्तिमान् ।
विद्युत्-शुभ्र-असित-रजः-श्यामानि अस्य मुखानि तु ।
जटा-अवबद्ध-इन्दु-कलः प्रिया-युक्-नाग-भूषणः ॥

That Rudra (रुद्रः) should be meditated upon (ध्येयः) who:
is five-faced (पंच-मुखो);
is resplendent with the pure lustre of crystal (स्फटिक-अमल-कान्तिमान्);
has faces (अस्य मुखानि तु) that are verily:
Lightning-bright (विद्युत्), White (शुभ्र), Dark (असित), Reddish-brown (रजः), and Cloud blue (श्यामानि);
bears the crescent moon (इन्दु-कलः) bound (अवबद्ध) in His matted locks (जटा);
is with His beloved (प्रिया-युक्); and
is adorned with serpents as ornaments (नाग-भूषणः).

Notes:

This Dhyaana shloka is given to us by Srimad Acharya in तन्त्र-सार-सङ्ग्रह (4.77-78) for जप and is also used in daily pooja for abhisheka to Rudra.
Just as स्फटिक (quartz crystal) reflects light purely but cannot create its own, Lord Narasimha is the fundamental energy force that shines through Shiva the pure.
The five colored faces represent Shiva’s qualities of Sattva (White), control over Rajas (Reddish-brown) and Tamas (Dark), as well as his energy (lightning) and austerity (cloud).