Inestimable vs. précieux

While both 'inestimable' and 'précieux' in French convey high value, they have subtle differences in usage and connotation.

Inestimable

'Inestimable' means something so valuable that its worth cannot be measured or calculated. It often implies uniqueness and irreplaceability.
Les conseils de mon grand-père sont d'une valeur inestimable.
(My grandfather's advice is of inestimable value.)
Cette découverte archéologique est inestimable pour notre compréhension de l'histoire.
(This archaeological discovery is invaluable for our understanding of history.)

Précieux

'Précieux' means precious or valuable, but can also imply delicacy, refinement, or something cherished. It's more commonly used for tangible objects or personal relationships.
Ce collier en diamants est très précieux.
(This diamond necklace is very precious.)
L'amitié est un bien précieux qu'il faut cultiver.
(Friendship is a precious asset that must be nurtured.)

Summary

While 'inestimable' is used for things of immeasurable, often intangible value, 'précieux' is more versatile, applying to both valuable objects and cherished relationships. 'Inestimable' emphasizes incalculable worth, while 'précieux' can indicate both high value and emotional attachment.