It was 30 years ago that a British woman bought what everyone thought was just a piece of costume jewellery.

Discovering the giant ring at a car boot sale, she picked it up for a tenner. But, boy, was she in for a surprise.

The “one-off windfall” is now expected to fetch around £350 000 (R5,8 million) in July when it is auctioned off by Sotheby’s London, reports TIME:

It turns out that the dusty gem — which the owner assumed was a fake and wore regularly in her daily life about town for decades — is actually a giant, 26-carat cushion-shaped white diamond from the 19th Century, giving it that eye-watering price.

The antique shape and older style of cutting had disguised its true brilliance for all those years.

The woman – who want to remain anonymous – is pretty excited about the prospect of the sale, “even though [she] will be short one of her staple rings”.

Shame, I guess she will just have to make do.

The owner could always use the money to buy herself a tanzanite stone if her finger feels a bit naked.

Local suppliers Diamond Jewellery International have the second best deal of a lifetime (after her £10 discovery), offering a 50% discount off all tanzanite jewels.

Read all about tanzanite’s interesting – and recent – history here.

If you’re interested in finding a stone or two, contact Diamond Jewellery International here, or email henk@2oceansvibe.com, and you just never know what you might walk out with.

A nice little shade of blue is definitely not a bad look.

[source:time]