The earring post is made in the same metal as the earring it's part of, which matters most at the piercing channel. For sensitive ears, the purity of platinum and high-karat gold is what keeps the contact point neutral.
A Notable Quality
Standard clutch backs are designed to sit flat against the earlobe with a low profile that minimizes pressure during extended wear. For those who find standard clutches uncomfortable, comfort backs, which are a variant with a larger padded surface, distribute earring weight across a broader area of the lobe.