Anglo-Saxon gold and silver found in a field in the West Midlands has been declared treasure trove and part of the Staffordshire Hoard.

The 81 items, which date to the seventh century, will be handed to the British Museum's valuation committee to assess their worth, South Staffordshire coroner Andrew Haigh told an inquest in Stafford on Friday. It will then be up to Staffordshire county council and neighbouring councils to raise the money to buy the new items for the nation. The original hoard, with 3,900 items, was bought for £3.3m after being found in a field near Lichfield in 2009 by metal detectorist Terry Herbert. He split the money with Fred Johnson, the farmer who owned the land. Though a team from Archaeology Warwickshire discovered the second haul last year, proceeds from the sale will once again go to Herbert and Johnson. The most interesting finds included an eagle mount, whose use is not known, and a cheek piece from a helmet.

Philip Atkins, leader of Staffordshire council, said it and the owners of the original hoard, Stoke-on-Trent and Birmingham councils, would now have to look at raising money to buy the new items.

"Last time we raised £1m in public donations in just 12 weeks. This time we won't need nearly as much money, but I would encourage people to donate. It's important for our region that the hoard stays together. Just as York is associated with the Vikings and Bath with the Romans, so too will Lichfield be connected to the Anglo-Saxons," he said.

If the money is raised, the pieces are likely to end up in the Stoke Museum and the Birmingham Museum, where much of the original hoard is on show. Over a million people have seen it, said Atkins.

Despite the initial outlay, the hoard has been a money spinner for the museums, with cash raised by loaning items to Washington and also by co-operating with film-makers from the Discovery Channel.

Evidence was given in the coroner's court by Dr Kevin Leahy, an archaeological finds specialist who catalogued the original hoard and the new items, and principal archaeologist for Staffordshire, Stephen Dean.

Dean described how a team of archaeologists returned to the field in November last year and in two phases recovered the pieces from the ground, including gold and silver items, hilt rivets and pommel caps from swords and small fragments of metal discs, made of either copper alloy or base silver.

Experts agree there is little chance of any more finds coming from the field.

Leahy said that the finds had "roused the public's interest" in a period of history which had until recently been considered the dark ages.

"This is a period which runs for twice that of the Roman period, and which shows Anglo-Saxons were highly cultured," he said.

Some of the gold in the pieces from the original Staffordshire Hoard could be traced to Istanbul in modern-day Turkey, and the gems to India and eastern Europe, showing the Anglo-Saxons to be accomplished traders.

At the end of the hearing, the coroner ruled 10 of the total of 91 items discovered in phased investigations starting on 19 November 2012 were not to be considered treasure, mostly as they were modern "waste" material.

These items will all be returned to the owner and finder.