Although Emeralds are a 7-7.5 on the MOHS scale their crystal make up makes them extremely brittle so a knock or blow to the ring can cause chipping, cracking etc. You should also
never get Emeralds near hot water - this can also cause cracking and ultrasonic cleaners are a complete no no. To clean you use a soft baby toothbrush, tepid water and either a baby soap or a washing up liquid.
Most emeralds on the market today have been oiled and they can be re-oiled by specialist jewellers every 3 or 4 years or so. However, treatments to Emeralds are not just about oiling now. Unfortunately some are filled etc etc. Here's a useful article for you to read - it gets a bit technical in places but the table of treatments is useful.
http://www.ruby-sapphire.com/catfights.htm
This is easy reading and very informative:
http://jcrs.com/newsletters/2007/2007_11.htm
Basically if you buy an Emerald, ask the seller (and that includes TJC) what specific treatments your gemstone has received. That way you'll have a better idea (or your jeweller will) on how to care for it.
In terms of what's better? Colombians are considered (overall) to be the finest quality BUT you can buy dreadful Colombians and beautiful Zambians so in all honesty quality should be judged stone by stone.
What should you look for? A gorgeous colour - Colombians can be slightly lighter and more blue/green, Zambians can be a darker green but of course that's a generalisation. Siberian Emeralds can give the very best Colombians a run for their money in terms of colour and clarity but are much rarer on the gemstone scene. Choose a colour that speaks to you! Of much more importance is clarity. TJC presenters often say that you should never buy an Emerald that doesn't have "jardin" (inclusions). Absolute total rubbish! Emeralds with very little inclusions will always be more valuable!!!! So look for one where the jardin doesn't take over the look of the Emerald.
One other thing to be aware of........... if you've had an Emerald valued in the last few years you may have been surprised that they're not a gemstone that has risen much. So typically a valuation of 5-8 years ago will be about the same today.
At the end of the day don't be afraid to buy an Emerald, just be aware of the care it needs. My Mother inherited an Emerald ring (now mine) and she wore it nearly every day of her life. It's still intact and I'm attaching a picture below. Apart from one tiny inclusion it's practically jardin free! By the way, the "inclusions" you can see in the photo are actually water because I had just cleaned it and it hadn't dried properly! :54:
This ring is over 100 years old and a Colombian at its best!
This is also a Colombian (see how much lighter it is in colour and more blue). This stone does have jardin but they don't detract from the overall look and as its 3ct I could forgive it a few inclusions!
Please post piccies if you buy one won't you?
