A television documentary billed as the first time Queen Elizabeth II has spoken on camera is certainly no small event. This is, after all, a notoriously camera-shy monarch, whose belief in the need to wrap herself has been both unflinching and spectacularly successful. As other royal houses fell, hers has only grown in power.

Far more startling, though, is that despite The Coronation (Sunday, 7.40pm, ABC1) being dominated by hundreds of carats of the world's most precious gemstones fashioned into two over-wrought crowns, the Queen still sparkles in a way that almost doesn't permit you to take your eyes off her. She is, in the face of all that glitter, still very much the star of the show.

The documentary's focus is two key pieces of the Crown Jewels – St Edward's Crown, which the Queen has worn only once, at her coronation, and The Imperial State Crown, which she wears to big-ticket royal occasions, such as the state opening of parliament – and a handful of supporting pieces, such as the sceptre and orb, the ampulla and spoon (which are used to anoint the sovereign) and a few other bits and bobs.

The interview, such as it is, was plainly brief, making up only a fraction of the documentary, and spread thinly throughout. The host, former herald and coronation historian Alastair Bruce, is effective, if a little cowed. Hard to criticise him on that front; the cult of mystique built up around the Queen would no doubt make her presence overpowering.

But the strength of the documentary lies in its intimacy. The Queen pokes at the crowns with some curiosity. And remarks casually – "Weighs a ton!" – when handling St Edward's Crown, by a long measure the one which captures her fascination.

By anyone's measure the Crown Jewels are glittering. But in real terms they're a bit overwrought and far from the rock stars of the Queen's jewellery collection. Those sexier pieces – which come with truly remarkable histories – include the George III tiara (the one with tall diamond spikes), the Vladimir tiara (the one with diamond circles and dangling emeralds), the Prince Albert brooch (the one with the honking big sapphire) and "Granny's Chips", also known as Cullinan III and IV, a brooch of two giant diamonds.

The last of those does make an appearance in this documentary, reunited with the larger Cullinan stones that are mounted in the head of the Sovereign's Sceptre and the Imperial State Crown. It is, the Queen notes, the first time since the coronation that all the pieces of the Cullinan diamond have been back in proximity to each other, the two giant stones in her brooch considered the off-cuts of the larger stones.

The notion that this is the first time the Queen has spoken on television is plainly untrue, though it makes for good marketing. It is the first time she has been questioned on television, though when you consider the questions are focused on the coronation jewels, and were no doubt approved ahead of time, the impact of even that is lessened.

In truth she has spoken in several documentaries, and answered questions on mike but off camera. If you want insight into her world, there are better documentaries which have done that.

What you do get, however, is startlingly intimate. And in reuniting the Queen with coronation regalia she has not physically handled since her coronation day, something properly historic.