It is now the middle of May, and here in Canada we are heading to the May 24th long weekend. This is traditionally the weekend of opening the cottages, planting our flowers and other garden items. It is what we think of as the start of summer and many head for campsites. However this year is a much colder spring, so I find myself this weekend thinking of heading to warm tropical beaches. I am not saying I am going only dreaming of it.
Do you know what happens when a gemmologist dreams of places? The thought process no matter how we try to leave work behind is: what gems are found there? You see, for most gemmologists work is also a passion, so it is always with us. We will travel the world and will always look for the museum that has the jewellery or gem collections. A good one in my area is the Gem and Mineral Gallery at the ROM in Toronto.
Back to the beach now. What do I think of besides surf and sun? Pearls! Amber! Larimar! Today though it is pearls. It is also the traditional birthstone of June so another reason to talk about pearl.
If you think back in history you will find lots of pearls. They were considered very valuable and if you wanted to gain favour of a king, why you offered him pearls. Julius Caesar when crowned emperor of the Roman Empire was crowned with a pearl diadem.
The main components of pearls are calcium carbonate (CaCO3). Pearls are found in both saltwater and freshwater bivalve mullosks. When natural, the pearl is formed as nacre is secreted around an irritant that has entered the bivalve creature and it wants to protect itself. What is the irritant is still being debated, but it is thought to be anything from a grain of sand to a minute snail or a parasitic worm. Whatever the irritant, this is called the nucleus.
When pearls are cultured, this irritant is introduced by man. In freshwater this may be a piece of the mantle (a membrane that secrets nacre and lines the shell surface of mollusks). Saltwater cultured pearls usually have a bead nucleus of shell or mother of pearl along with the mantle. Different shapes and sizes can be created depending on what is inserted as nucleus.
When looking at pearls there are a few things to look at:
Colour–first the main body colour and then the overtone of colour. White, silver, rose, black, cream, yellow, pnk etc.
Shape: see everything from round to off round to totally baroque pearls.
The lustre of a pearl can be anywhere from dull to mirror like lustre. Pearls that have good lustre but have dead spots of dullness are not pearls that you want.