Hello and thank you for your question.
The starting point in sorting this out is to define the term "gem."
"Gemstones have attracted humankind since ancient times, and have long
been used for jewelry. The prime requisite for a gem is that it must
be beautiful. The beauty may lie in colour or lack of colour; in the
latter case, extreme limpidity and "fire" may provide the attraction."
What are gemstones?
http://www.multicolour.com/catalogue/source/
So based on the above, the answer to the last part of your question is
yes, if it's a stone and it's colored, it's a gem. And as you'll see
below, gems are either precious or semiprecious, although the
distinction is somewhat out of fashion.
According to the International Gem Society, it's no longer appropriate
to distinguish between 'precious' and 'semiprecious' gems:
"A couple [of] centuries ago the terms “Precious” and
“Semiprecious” gems came into common use. There are so many exceptions
to this classification, that it no longer has any value. For example
diamonds have always been considered precious gems, yet there are
diamonds that sell for $100 a carat....
On the other hand there are garnets that sell in excess of $1,000
a carat. Garnets have traditionally been considered semiprecious gems,
but some of them are worth more than ten times what a low quality
diamond is.
These terms are still used occasionally, but they are frowned
upon. The U.S. Federal Trade Commission, (which sets legal
definitions,) has considered making it illegal to use them because
they can be deceptive."
http://www.gemsociety.org/info/igem8.htm
But many sellers continue to use the terms, especially when they are
selling 'precious' stones. For example,
"Gemstones are divided into two categories: precious stones and
semiprecious stones. Precious stones are the rarest and most valuable
gems. There are only four precious stones: Diamond, Ruby, Sapphire,
Star Sapphire and Star Ruby, and Emerald"
JC Penney
http://www.jcpenneyinc.com/guide/jewelry/gemstone/precious.htm
According to encyclopedia.com only diamond, some forms of corundum
(ruby, sapphire, Oriental emerald, Oriental topaz and Oriental
amethyst) and emerald qualify as precious stones (plus they classify
pearl, although organic, as precious).
http://www.encyclopedia.com/html/section/gem_typesofgemstones.asp
In summary, if it's a colored stone, it's a gem. Beyond that, there
are traditionally 'precious' stones, and the rest are semiprecious.
But we'll give the FTC the last word on the proper use of these terms
in today's market:
"§ 23.24 Misuse of the words "real," "genuine," "natural," "precious,"
etc.
It is unfair or deceptive to use the word "real," "genuine,"
"natural," "precious," "semi-precious," or similar terms to describe
any industry product that is manufactured or produced artificially."
Guides for the Jewelry, Precious Metals, and Pewter Industries
http://www.ftc.gov/bcp/guides/jewel-gd.htm#§%2023.24%20Misuse%20of%20the%20words%20"real,"%20"genuine,"%20"natural,"%20"precious,"%20etc.
Search terms used:
precious semiprecious definition stone
ftc gem guides
Thank you again for your question. If you find any of it unclear,
please request clarification; I would appreciate it if you would hold
off on rating my answer until I have an opportunity to reply.
Sincerely,
Google Answers Researcher
Richard-ga |
