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Most Valuable Gemstones

The Most Valuable Gemstones      Precious Gems

There are two kinds of Gemstones: Precious and Semi -Precious.

Only seven gemstones- Diamond, Aquamarine, Emerald, Sapphire, Ruby, Topaz, and Opal- are regarded as precious.


Stud ear rings. Princess Cut White Diamond Loose Gemstone (2cttw, H-I Stone, VS2 Clarity)
Diamond    The Australian Diamond.

Diamond –is an outstanding natural material. It Hardness, high lustre, fire and clarity makes it unique. Marilyn Monroe song Diamond being a girl’s best friend. How right she was.

Now something about diamond, I would love to be able to understand more about how to find diamonds.

Diamonds originate in the earths mantle. They are usually transported to the surface in volcanic pipes of kimberlite or lamproite  rock. From  these they wash into rivers and often finish up in alluvial deposits far from their source .However, some eastern Australian diamonds are unusal and may come from a source other than the typical kimberlite or lamproite.

Diamond is the hardest mineral on earth. Diamond-tipped drill and saws can cut through any substance. The glittery brilliance of the diamond makes it the most valuable gemstone in the world. Hardness is 10.  


Diamond is used to cut a lot of other stones and rocks, Diamond- tipped drills and saws are used to cut and drill through meters of dirt to find water or other minerals. Also in a smaller scale to cut and polish gemstones for jewellery.

dia1How do you know what a diamond looks like. Diamond hardness is a 10. It can cut any material, and nothing will stick to it.  The picture to the left shows a sparkle rock on the side of another rock.

I need to know more. Well The chances of finding a diamond are 1 in 10,000,000.Diamonds are cubic (isometric) form. The most common mineral that looks like a diamond is quartz and it is hexagonal form.When looking down on the crystals from the top, with the point of the crystal aimed at your eye, quartz will have six sides and a diamond will have four sides. Topaz has eight sides.

Don’t scratch glass-most gemstones will do that. The only hardness test that will identify a diamond is Scratching  Corundum. Corundum, which includes all Rubies and Sapphires Gems, is 9 on the hardiness scale

What is Corundum

Corundum is an aluminium oxide that commonly forms hexagonal barrel-shaped prisms that taper at both ends or as thin tabular hexagonal plates. Its hardness of 9 on the mohs scale, making it one of the most durable commercial  gemstones. Comes in all coloured of the rainbow. Red Is ruby.


What is Ultramafic.

Describing igneous rocks that contain magnesium and iron and only a very small amount of Silica, such as are found in earth’s mantle.

What is Kimberlite.

Kimberlite, an ultramafic volcanic rock , is quite rare but much sought after because it is the ore of diamond

Kimberlite is a peculiar rock that erupts very rapidly from the deep in the earths mantle, leaving behind a narrow pipe of this greenish brecciated lava. The rock is of ultramafic compositionvery high in iron and magnesium and is largely composed of olivine crystal in a groundmass consisting of various mixtures of serpentine, carbonate minerals, dropside and phlogopite. Diamond and many other ultra-high pressure minerals are present in greater or lesser amounts. With the Volcano  Eruption ,carries the kimberlites – along with any diamonds they contain – to the surface.

What is lamproite

Lamproite-  A variety of lamprophyric extrusive rock rich in potassium and magnesium.

Kimberlite and Lamproite – Host rocks for Diamond.

Rock Kimberlite with Diamonds
Rock Kimberlite with Diamonds

Kimberlite is very difficult to recognize. It Is basically a potassic  peridotite and comes in a variety of colours and textures.





Rough Ruby Gemstone
Rough Ruby Gemstone

Ruby are variety of mineral corundum. Ruby Deposits however, are rarer than sapphire deposits because they are dependent on the presence of the element, Chromium.Chromium gives ruby its red colour, with modification from iron, titanium and vanadium. Ruby is usually found in metamorphic rocks. Found Hart range in the northern territory. 10 hour drive from where I live. A Place I will be going to one day ( It host a lot of different gemstones)




Emerald is  the most famous and valuable green gemstone. Dark green is the most valuable colour of emerald, the light colour are of no value.



Sapphire is a gem varieties of mineral corundum, an aluminium oxide. This mineral is coloured by additional trace elements  in its structure. Sapphire come in all colours. except red which is ruby.

Look out for more information on Precious Gems. coming soon.

Have a great day.



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