свой глаз - алмаз

• СВОЙ ГЛАЗ - АЛМАЗ (, А ЧУЖОЙ - СТЕКЛО; СВОЙ ГЛАЗ <ГЛАЗОК> - СМОТРОК{{}}

[saying]

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⇒ it is preferable to see sth. oneself and make one's own conclusions, as opposed to relying on another's interpretation of it:

- - your own eye is the best spy;

- it is better to trust the eye than the ear;

- one eye has more faith than two ears.

     ♦ ...[Коровьев] выложил председателю пять новеньких банковских пачек. Произошло подсчитывание, пересыпаемое шуточками и прибаутками Коровьева, вроде "денежка счёт любит", "свой глазок - смотрок" и прочего такого же (Булгаков 9) Не [Koroviev] stacked five bundles of new bank notes before the chairman. There was a careful count, interspersed with Koroviev's little quips and pleasantries, such as "money loves to be counted," "your own eye is the best spy," and so on in the same vein (9a).