What is the stone achelamah,colour,properties,location?

Dear stoney4,

The correct name of the stone is actually "achlamah", also "ahlamah".
It is the biblical Hebrew name for the gem quartz we know as amethyst.

Amethyst occurs in a wide range of purple shades, ranging in color
from pale lilac to deep purple.  The purple color can be throughout or
can be in bands with white quartz. The pale colors are sometimes
called "Rose de France". The deep colors are the most valuable,
particularly a rich purple with rose flashes.

The crystals of the amethyst are hexagonal and can occur as tall
prismatic crystals or short stubby ones (Crystal system: trigonal).
Often the crystals have horizontal striations on their sides or faces.
The amethyst's hardness is 7. Cleavage: none.

Amethyst can be found in many areas around the world, including
Mexico, Brazil, Uruguay, Bolivia, Argentina, Zambia, Namibia, Russia,
Canada and the United States. In North America, Amethyst can be found
in Montana, Arizona, Colorado, Maine, New Jersey, near Thunder Bay and
in Nova Scotia.

Additional information on the achlamah-amethyst and its properties,
including its roles in religion and mythology, can be found on these
websites:

University of Oxford: Amethyst
http://www.chem.ox.ac.uk/mom/amethyst/default.html

International Colored Gemstone Association: Amethyst
http://www.gemstone.org/gem-by-gem/english/amethyst.html


Sources:

Straight Talk: Israel's Symbols and Heraldry
http://asis.com/~stag/symbols.html

Jewish Heritage Online Magazine: Twelve Gems and their magical Qualities
http://www.jhom.com/topics/stones/gems.html

World ORT: Exodus - Tetsaveh
http://bible.ort.org/books/torahd5.asp?action=displaypage&book=2&chapter=28&verse=18&portion=20

Search God's Word: Old Testament Hebrew Lexicon - Achlamah
http://www.searchgodsword.org/lex/heb/view.cgi?number=306

Search terms used:
achelamah
://www.google.de/search?q=achelamah&hl=de&lr=&ie=UTF-8&oe=UTF-8&newwindow=1&filter=0
stones Tarshish benjamin
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=stones+Tarshish+benjamin&btnG=Google+Suche
ahlamah
://www.google.de/search?q=ahlamah&ie=UTF-8&oe=UTF-8&hl=de&btnG=Google+Suche
amethyst
://www.google.de/search?q=amethyst&ie=UTF-8&oe=UTF-8&hl=de&btnG=Google+Suche
achlamah
://www.google.de/search?q=achlamah&ie=UTF-8&oe=UTF-8&hl=de&btnG=Google+Suche

Hope this is what you were looking for!
Regards,
Scriptor