Let’s speed up spread of broadband by separating Openreach from BT Crown jewels miner Petra Diamonds loses its sparkle The precious gem producer has seen a sharp fall in sales and profits as weak Chinese demand has sent diamond prices lower Petra Diamonds unearthed the gem which now adorns the Sovereign's Sceptre, part of the British crown jewels collection.
Take context from the input text and decide on the accurate relationship between 'Petra Diamonds' and 'diamond' from the options provided.
Options: employer, publisher, industry, product/material produced