jewelry tarnishes. Why even gold jewelry can blacken skin or
WHY JEWELRY SOMETIMES BLACKENS THE SKIN OR CLOTHING
Blackening or discoloration of either the skin and clothing or
the jewelry itself is certainly very annoying. There are several
causes for these occurrences, as discussed below.
(The following information provided courtesy of the Hoover and
Strong Refinery, Inc.10700 Trade Road, Richmond, Virginia. For
the original sources see the footnote credits at the bottom of
Make-up present on the skin or clothing is the most common cause
of the blackening or smudging. Cosmetics often contain chemical
compounds which are harder than the jewelry itself. Metallic
abrasion occurs when these hard compounds come in contact with
the jewelry metals and wear or rub off very tiny particles of
metal which appear as jet black dust. Very finely divided metal
always appears black rather than metallic. When this dust falls
on absorbent surfaces, such as the skin or clothing it sticks,
forming a black smudge.
To prevent this, cosmetics which contain zinc oxide, titanium
dioxide, ferric oxide, and calamine should be avoided. If this
is not possible we recommend that you remove rings and other
metal jewelry while applying cosmetics. Also, clean with soap
and water those skin areas which will be in contact with your
jewelry. Be sure any cosmetics, perfumes, etc. are dry before
putting on your jewelry.
Another cause of discoloration is due to the corrosion of the
metals from which the jewelry is made. Pure gold, 24K, itself
will not corrode but is too soft for many kinds of jewelry and
therefore is alloyed with proportions of base metals, usually
silver or copper to make it harder. The composition of 14 karat
gold is 14/24 pure gold and 10/24 alloys. Only the base metal
used for alloying corrodes, leaving the gold untouched. The chemical
compounds of silver and copper which are formed turn very dark
even when slightly corroded.This corrosion occurs under moist
or wet conditions.
Our skin on which the jewelry lies, is provided with thousands
of perspiration glands. Chemically the perspiration is mostly
fat and fatty acids. These essentially mild chemicals are enough
to cause corrosion of 14 karat gold especially when aided by
warmth and free access of air. When this happens we suggest that
you remove your jewelry often and use an absorbent powder, free
of zinc oxide, on the skin areas which come into contact with
Rings containing copper and silver alloys, particularly sterling
silver, corrode readily on the skin if enough salt is present.
Simply exposing the hands to salted nuts, crackers, or popcorn
can cause such corrosion and discolor the skin. Rings should
be taken off when you must expose your hands to salt.
TARNISHING OF STERLING SILVER
Sterling silver is copper-silver alloy and is somewhat softer
than most gold alloys. Therefore, it is more likely to be abraded
to black dust by relative movement between the jewelry and the
skin or clothing.
Sterling silver jewelry has a pronounced tendency to tarnish.
The tarnish is always due to the contact with sulphur compounds.
The main cause of tarnishing of silver is a trace of hydrogen
sulfide gas in the air. This gas is particularly present in smoke
from burnt raw fuel, such as coal or oil; in some strong smelling
foodstuffs, such as eggs and onions; in some fish or shellfish;
and in polluted air.
The tarnish may turn the jewelry black and may also be rubbed
off on the skin or clothing. A few people with especially moist
skin may find that the sterling silver stains their skin green.
This is due to the copper component of the silver alloy. When
this occurs you should polish your jewelry frequently and use
an absorbent powder on those moist skin areas which come into
contact with your jewelry.
OTHER PROBLEMS AND SOLUTIONS
Soap, detergent, wax, polish, and cosmetic creams may build up
under a ring, causing a type of dermatitis. A burning sensation
and redness of the skin results. To prevent this, you should
remove all rings before using soap or detergent, and clean the
The wearing of silver jewelry when manipulating photographic
chemicals or solutions may cause staining of the skin. When silver
is attacked by a chemical solution such as nitric acid, the solution
of silver salt formed is reduced back to silver by the skin.
This silver is in a finely divided form and causes an intensely
black stain. Silver jewelry should be removed before working
with photographic chemicals or solutions.
Medications in the wearer's system, especially certain antibiotics,
can also cause jewelry to blacken or discolor. In in some rare
cases, the wearer's basic body chemistry reacts to the alloys
in both gold and silver and cause tarnishing. A solution to both
of these situations may often be had by wearing a higher karat
of jewelry: 18K or 22K instead of 14K.
This information is not offered as an excuse, but to clarify
the reasons, provide the facts, and offer solutions for those
who may encounter the problems described.
Fisher, Dr. Alexander A, What
Causes Gold Smudge, Jewelers Circular-Keystone, March 1971.
Gardam, D.E., Why Jewelry Sometimes Blackens the Skin or the
Clothing, The Worshipful Company of Goldsmiths, Special Report
No. 4, October 1989.