God's Word teaches that Christians should exemplify modesty and discretion in their personal attire and adornment. Used in this manner, jewelry has its place and is mentioned favorably in the Bible (Ezekiel 16:11-13; Genesis 24:53; Luke 15:22).
Two New Testament scriptures mention adornments: I Timothy 2:9-10 and I Peter 3:3-5. Neither of these texts prohibits tasteful use of jewelry and adornment. But going to extremes—being obviously motivated by personal vanity—is condemned.
The "braided hair" or "arranging the hair" mentioned in these passages in the New King James Version refers to elaborate interweaving of the hair with gold ornaments, jewelry, or even wreaths. It is showy display—the vanity and pride—that is wrong, not the use of gold or jewelry.
The overall Bible principle regarding the use of jewelry or cosmetics, then, is that we practice modesty and tastefulness, rather than draw attention to ourselves. Our character, instead of our appearance, should be the most memorable quality about us.