Thursday 21 July 2011

Summer

Are we to expect our Summers to be like this from now on? Global warming? Really?

Anyway, we do have some very lovely pieces of jewellery for the summer. In particular some very pretty porcelain jewellery by the German house of Nymphenburg.

Porcelain is made of three basic ingredients, kaolin, feldspar and quartz.
These three are ground very fine, mixed together and has water bubbled up through it.
This mixture must rest in a humidity controlled environment for up to two years before it is ready to use. When ready it is turned into a a workable and pourable mix which is filtered into moulds.
Moulds must be replenished after 300-400 uses to maintain definition.
Hand finished and dipped in a liquid slip (glaze), the pieces are fired several times with one very intense firing at 1260 degrees making the porcelain impervious to water. The porcelain can shrink up to 20% whilst being fired, taking away all remnants of water content.

The finished item!

Beautiful.

Now, what summer birthstones do we have? For the fiery and siummery month of July it is the hot and fiery Ruby. August boasts the ever lovely Peridot, a mossy/bottle/khaki green stone which is clean, clear and crisp. And with September round the corner, a whole array of colour from the Sapphire.

Rubies are very rare gems.
They exist in many shades of red from pinkish to purplish to brownish and reddish.The red colour is determined by the amount chromium, which further enhances the colour by causing a red fluorescence. A ruby's brownish colour indicates iron. From the Latin name "rebeus", the true ruby has sometimes been called "oriental ruby" to distinguish it from the red spinel.


                                      Peridot is the gem quality variety of the mineral "olivine".
A rock forming mineral, olivine occurs in silica-poor igneous rocks, such as basalts, gabbro, troctolite, and peridotite.
Peridots shades of green are caused by the presence of iron, and it often has a greasy lustre.
The mineral is named from the French word "peritot" which means "gold" because the mineral can vary towards that colour.


Sapphires come in a variety of shapes and sizes - and colours.
Every colour except red in fact as red sapphires are actually rubies.
Most sapphires are heat treated to eliminate impurities and to improve a gems colour and clarity. I prefer the term "enhanced" as treated makes it sound as if there's something wrong with a stone.
Cornflower blue sapphires are most desireable.