Med flygtransport: upp till 10000 € och inte tyngre än 50 kg. Jag tror att förlovningsringen skulle passera dessa kriterier.
The goods for private use except transport vehicles imported on customs territory of customs union in accompanied or unaccompanied luggage
Goods for private use (except ethanol and the indivisible goods) transported by air transport: customs cost of which does not exceed the sum equivalent of 10 000 euros and gross weight of which does not exceed 50 kgs
Källa: Federal Customs Service of Russia .