a polished white quartzite

This quartzite has a glossy finish to it, with most of the stone being a brilliant white. At a closer glance, there are slender bevels of dark grey within the centre of the stone that branch into finer traces of a lighter grey until the swirls of colour fade away.

It is a polished white quartzite.
It weighs about an ounce.

You identify a polished white quartzite.
It weighs one ounce, and it is worth about one lauren.
Its keywords are quartzite, white, polished, gem, and jewel.
When embedded, it can be used to call upon the Valar.