Spiaggia dell'Innamorata, Elba

What Seaglassmap found here

A 280-metre bay under Capoliveri on Elba's south-east coast: dark sand through the middle, stone and rock at the western end, which is where the glass is. Expect a few pieces, not a haul. The one first-hand account we trust calls the glass "not plentiful" but jewellery-quality, and this is a serviced beach worked over all summer. Best in spring, before the season. Elba is a national-park island and the park asks visitors plainly not to carry its sand, stones or shells away.