Shiva Purana
गम्भीरनिनदः शंखो हंसकुंदेन्दुसन्निभः ॥ आस्वपृष्ठादिदेशेषु रत्नचामीकराचितः ॥ ३१ ॥
The conch shall be white like the swan, Kunda flower or the moon. It shall have a majestic resonant sound. At the mouth, back and other places it shall be studded with gems and framed in gold.
english translation
gambhIraninadaH zaMkho haMsakuMdendusannibhaH ॥ AsvapRSThAdidezeSu ratnacAmIkarAcitaH ॥ 31 ॥
hk transliteration by Sanscript