Gem Stones?

Question

What is the rarest gemstone

Answer 1

One that actually exists only in one piece on the entire earth.
Because of this, I think only very rare types of rock, well hidden in the mountains, undiscoverded yet, might be the rarest.

There are many gems but the availability depends on the geographical region.
Could be the most pure white diamond, flawless standard.
Could be some local gems, known only by the local tribes.

Could be outside plannet stones.Such as the rocks they brought from the moon.

OOPS, LOOK ARTICLE:
Distinguished by its intensely bright beauty and rarity, ammolite burns with its own unique multi-colored ‘fire’ and no two stones are ever the same. 70-75 million years have passed since this wonder of nature was born, yet it only entered the World market in the 1960’s.

Captivated by the magical beauty of ammolite, enchanted by the fact it is the rarest of all gemstones, and delighted to know the finest iridescent gems are found only in my home country of Canada, I did some research to find you an exceptional source for ammolite jewelry (link is provided at the bottom of the article), and asked our gemology expert, Barbara W. Smigel, PhD. Graduate Gemologist, GIA, for her comments about this remarkable gem.

Barbara tells us, “This gem is the result of the fossilization of extinct, shelled mollusks, called ammonites which are related to today's Nautilus. Although many different ammonite fossils are found in many world locations, only two of the many species found just in a restricted area in Southern Alberta, Canada show the iridescent effect, which has preserved, and enhanced, the thin, tablet-like aragonite crystal layering of the shell.

comment: the rarest gem is not the most expensive one
the most expensive one is diamond, cause it has durity 10 on scale, and the bigger the better

I followed the link provided by the orangetulip and there says that coloured diamonds are expensive because they are very rare, only 1/10,000 of the diamonds are with colour shade.
And red diamonds are the rarest. But I think red diamonds are rubis, green emeralds,pink and yellow are pink and yello and blue are sapphires

Answer 2

Of the diamonds, red diamond is the rarest. But it is not the rarest gemstone.

Painite is the rarest as there are only 18 known specimens.

Serendibite, Grandidierite, Poudretteite, Majorite, Jeremejevite, Taaffeite, Musgravite and Benitoite are the other rarest gems in the world.

http://www.curiousnotions.com/home/gemstones.html

Answer 3

Currently the rarest gemstone is Tanzanite.It can only be found in the mines of Tanzania.

Answer 4

One of the rarest could be Tanzanite,due to the fact that it is mined in only one place,Tanzania. There is only one mine,and therefore that contributes to the high price of Tanzanite.

Answer 5

I believe it is the yellow diamond.