These vintage Sevres Crystal pieces are rare and highly collectable.
It has an Alexandrite Neomydium colour - which is a fine lilac purple colour in normal light and this changes to a blue or aquamarine when placed under fluorescent lighting.
It has certainly a very fine piece of French mid-century art glass - and is fully marked with the Crystales de Sevres mark on the base, as photographed. It is probably a bowl for the more specialist collector of vintage Sevres Glass.
It is a heavy piece and very chunky - with a lobed rim and inside impressed with a pattern of stars. It is in good condition with no damages.
It has a diameter of 6 inches - and a height of 3 3/4 inches. Unpacked it is 2.5 kg - so a bit of a beast, weight-wise. Sadly, this would prevent me from posting it outside of the UK.
UK Postage would be with Parcelforce48. This would cost £10 and be applied to your order the checkout.