There's an interesting passage in Ezekiel that gives us an insight into God's opinion of adornment and jewelery
This is God, speaking of Jerusalem:
7 I made you numerous like plants of the field. Then you grew up, became tall and reached the age for fine ornaments; your breasts were formed and your hair had grown. Yet you were naked and bare.
8 “Then I passed by you and saw you, and behold, you were at the time for love; so I spread My skirt over you and covered your nakedness. I also swore to you and entered into a covenant with you so that you became Mine,” declares the Lord God. <sup class="versenum">9 </sup>“Then I bathed you with water, washed off your blood from you and anointed you with oil. <sup class="versenum">10 </sup>I also clothed you with embroidered cloth and put sandals of porpoise skin on your feet; and I wrapped you with fine linen and covered you with silk. <sup class="versenum">11 </sup>I adorned you with ornaments, put bracelets on your hands and a necklace around your neck. <sup class="versenum">12 </sup>I also put a ring in your nostril, earrings in your ears and a beautiful crown on your head. <sup class="versenum">13 </sup>Thus you were adorned with gold and silver, and your dress was of fine linen, silk and embroidered cloth. You ate fine flour, honey and oil; so you were exceedingly beautiful and advanced to royalty. <sup class="versenum">14 </sup>Then your fame went forth among the nations on account of your beauty, for it was perfect because of My splendor which I bestowed on you,” declares the Lord God. Ezekiel 16
So, God, speaking of Jerusalem as a loving suitor does of a bride, speaks of adornments, including nose and earrings. There are also other texts which speak of both men and women having rings, nose as well as ear, as adornments. Certainly if God felt piercings to be sinful, He wouldn't portray them so positively in such a tender, loving, even sensual way.
For Christians, we need to remember that our outward appearance needs to be modest and that our true adornment is a gentle and quiet spirit. However, this doesn't mean that we cannot wear earrings or nose piercings... and I don't see any ban on piercing any other body part either...
These things tend to be very cultural and culture changes. For instance, if I were to go out to the store wearing what I wore today, capri pants and a short-sleeved t-shirt (it was quite hot today)... but wear it in the 1700's in Boston, it would be the height of immodesty and people would think me no better than a prostitute. However, the days of it being shockingly sinful for a woman to show her bare ankles are long, long gone.
The same can be said for piercings and tattoos. When I was young, these things were associated with drunken sailors, biker gangs and (as far as earrings on men) gays...
Not so any more. Tattoos and piercings are no longer considered immoral or immodest. For the Christian who gets them, we do need to keep in mind that we need to exercise self-control and be modest... so if one starts walking around with so many body piercings and tatts that it focuses all attention on one's personal appearance rather than one's inner spirit or especially one's gospel message, then one is most likely not exercising self-control or being modest.
One thing I do remind my kids of though... while rings can be taken out and piercings closed up... tatts are far more permanent. And, although it's quite fashionable, even faddish to have tattoos now, who knows how the fashion might change in a few years... It wouldn't matter to me if either of my kids get piercings (paid for by themselves)... but no tattoos... not until they are old enough to fully understand that a tattoo will be there for the long haul.
Of course that's me. Their father views things differently... Viola can get her lobes pierced when she wants, but Thomas... not Steve's son, no way.