Until the rise of the west, India was possibly the richest country in the world. Such a country presented an irresistible target for the ravening Mongols and their descendants who settled in present day Afghanistan, Uzbekistan, and Tajikistan, all within comparatively easy reach of north-western India. The northwest was, at this time, a mish-mash of warring kingdoms, more interested in sending scores with their neighbours than in unifying against the Mongols. It is then unsurprising that Mahmud Ghazni’s armies so handily defeated those of the Indian kings. Mahmud began a series of seventeen raids into northwestern India at the end of the 10th century. Nonetheless, he did not attempt to rule Indian Territory except for Punjab, which was his gateway to India.

Somnath Temple located in the Kathiarwar region of Gujarat, is one of the twelve Jyotiriings symbols of the God Shiva. It is mentioned in the Rig Veda. Somnath mean “The Protector of Moon God’. It is known as “the Shrine Eternal’ as although the temple has been destroyed six times it has been rebuilt every single time. The first temple of Somnath is said to have existed before the beginning of the Christian era. The second temple, built by the Maitraka kings of Vallabhi in Gujarat, replaced the first one on the same site around 649 AD. In 725 Junayad, the Arab governor of Sind sent his armies to destroy the second temple. The Pratihara king Nagabhata II constructed the third temple in 815 AD, a large structure of red sandstone.

Mahmud of Ghazni attacked this temple in 1025 AD, and looted it of gems and precious stones. He then massacred the worshippers and had the temple burnt. It was then that the famous Shiva lingam of the temple was entirely destroyed. The temple and citadel were sacked, and most of its defenders massacred; Mahmud personally hammered the temple’s gilded lingam to pieces and the stone fragments were carted back to Ghazni, where they were incorporated into the steps of the city’s new Jamiah Masjid.

However as very little evidences or descriptions of said era are available, there are multiple versions of this raid and what was probably looted during the raid.

Reference:

http://www.indianage.com/search.php

http://www.winentrance.com/general_knowledge/history/mahumud-ghazni.html