Não é grande. Quando Galadriel dá a Sam, ela diz:
'For you little gardener and lover of trees,' she said to Sam, 'I have only a small gift.' She put into his hand a little box of plain grey wood, unadorned save for a single silver rune upon the lid. 'Here is set G for Galadriel,' she said; 'but also it may stand for garden in your tongue. In this box there is earth from my orchard, and such blessing as Galadriel has still to bestow is upon it.
Mais tarde, no Shire, vemos:
Then suddenly one day, for he had been too busy for weeks to give a thought to his adventures, he remembered the gift of Galadriel. He brought the box out and showed it to the other Travellers (for so they were now called by everyone), and asked their advice. 'I wondered when you would think of it,' said Frodo. 'Open it!' Inside it was filled with a grey dust, soft and fine, in the middle of which was a seed, like a small nut with a silver shale. 'What can I do with this?' said Sam.
Portanto, não há nada como uma dimensão precisa, mas é uma "caixinha de madeira cinzenta simples" que contém "pó cinza, macio e fino" e uma "semente como uma noz pequena". Ele usa a poeira com muito cuidado, apenas um grão de cada vez:
So Sam planted saplings in all the places where specially beautiful or beloved trees had been destroyed, and he put a grain of the precious dust in the soil at the root of each. He went up and down the Shire in this labour; but if he paid special attention to Hobbiton and Bywater no one blamed him. And at the end he found that he still had a little of the dust left; so he went to the Three-Farthing Stone, which is as near the centre of the Shire as no matter, and cast it in the air with his blessing.
Existem muitos grãos de poeira em uma pequena caixa de "pó cinza fino" e se cada grão corresponder a uma árvore que é plantada pessoalmente por Sam ele tem uma quantidade enorme de trabalho para usar até mesmo uma pequena porção de poeira. Isso, novamente, aponta para uma pequena caixa.