Although many persons are content to collect gemstones in their
own right (just as others collect coins or stamps or other
collectibles), most gem lovers like to have their gems set in
jewelry so they can be worn on the person. Unfortunately, despite
the familiar refrain, diamonds, and other stones, are not
necessarily forever. Most stones are more or less brittle, many
are quite soft, and some can be damaged by heat, vibration, or
chemicals. It's too bad that most jewelers do not educate their
customers about how to care for their prized possessions. Here are
a few tips.
Stones that have a Mohs hardness of less than 8 are highly
subject to scratching; harder stones are less likely to be
scratched but are still subject to chipping and fracture.
Remember that quartz, with a hardness of 7, is one of the most
abundant minerals on earth, in the form of sand, or silica. When
removing dust from soft stones, it's usually best to rinse them
with clean water and dry with a soft cloth. Also, store jewelry
and loose gems in separate padded compartments or wrapped in
soft lint free cloth to prevent scratching, chipping, and
When cleaning nonporous gemstones, washing gently with a weak
solution of ammonia, rinsing with clean lukewarm water, and
drying with a soft lint free cloth is quite effective and safe.
Just be sure to plug the sink so you don't wash your stones down
the drain! On stones harder than quartz (Moh's hardness of 7),
it's safe to do a little gentle scrubbing with a soft
toothbrush, but if you're cleaning jewelry, be careful not to
scrub highly polished metal surfaces, as the slight abrasive
action of the brush will produce slightly hazy effects on the
metal. A little soaking may be necessary to remove heavier
If you use hand lotions or creams, remove your rings before
applying them! This will help prevent heavy buildup of dirt and
oil around your gemstones.
If you plan to do heavy or dirty work with your hands, remove
your rings so they will not be subjected to harsh blows,
abrasives, or unnecessary dirt. Even diamonds are relatively
brittle and can be chipped by a hard blow.
Pearls, coral, and porous stones such as opal, turquoise, or
malachite should be kept away from dirty water and oils to avoid
discoloration. Wipe them gently with a soft, damp cloth. Do not
wear rings containing these stones while washing dishes or
Be cautious about the use of ultrasonic cleaners. Some stones
are subject to internal stress -- tanzanite, opal, emerald,
organic gems (such as pearl, coral, and amber), turquoise,
lapis, and malachite, any stone containing major inclusions, and
most collector gems should not be exposed to ultrasound.
Tanzanite has been known to shatter and opals to craze under
ultrasound. Most emeralds and many rubies are "oiled" or
resin-impregnated, and ultrasound may remove the treatment or
expand existing fractures. If you are not absolutely SURE it's
safe, don't put your stones in ultrasound!
Diamonds are remarkably resistant to heat, but large stones and
those with major inclusions are sometimes damaged by jewelers
who linger too long with a torch during prong work. I've seen
several stones that required repolishing after a benchworker
allowed a torch to linger too long, especially when retipping
platinum prongs (because of platinum's high melting point). It's
often safest to remove them before working on a setting. Other
stones are less resistant to heat and should never be exposed to
extreme heat or sudden changes in temperature.
Opal, pearls, coral, amber, turquoise, and many collector gems
are quite heat sensitive (both to extremes and to sudden changes
in temperature). Do not leave them sitting in hot sunlight, near
radiators, or in hot cars. Once an opal begins to craze, it's
Brittle and soft stones should not be used in jewelry subject to
hard wear, such as rings that are worn constantly. They are much
safer in earrings, pins, pendants, or perhaps bracelets. They
can be used in rings that are worn occasionally, such as dinner
rings, but the setting should be designed to protect the stone
as much as possible. Even though opals are popular in rings, it
is a very hazardous use for them.
If one prong of a four-prong setting breaks, it often results in
the loss of a stone. Six prong settings are more secure. If a
prong is weak or broken, it's usually best to replace the head
than to attempt retouching prongs.
Sharp corners, such as the tips of pearshapes and marquise cut
stones, are especially susceptible to breakage and should be
protected by the setting. Also, faceted stones with shallow
crown angles (30 degrees or less), and thin or uneven girdles
are particularly prone to chipping and need extra protection.
Bezel settings offer more protection to stones, but they make it
more difficult to remove and reset stones if the stone needs
repolishing or if alterations of the metalwork are required.
Setting can also be hazardous. It's best to use high-karat gold,
which is softer and more easily bent into place. Also, consider
how the stone might be removed if necessary. Sometimes, it may
be best to use a false bezel setting and set the stone from
beneath, holding it in place with tabs.