The largest Moldavite ever found is recorded at 238 grams - it resides in the museum in Prague. In comparison, on January 25, 1905, at the Premier Mine in Pretoria, South Africa, a 3,106-carat diamond is discovered during a routine inspection by the mines superintendent. Weighing 1.33 pounds (590 grams) and christened the "Cullinan," it was the largest diamond ever found.
When you consider that these gems are made of a naturally fused glass created by the heat wave travelling in front of a meteor, that the molten glass splashed into the stratosphere and then solidified as it fell back to earth - estimated at a 20 mile drop - it's amazing any survived at all. Moldavites over 20 grams have always been considered to be rare and as the strew fields are depleted the opportunities to find large stones grows less and less. Purely from an investment point of view, size does matter. Moldavites over the magical 20 grams are hard to get even for someone like me - and I have the contacts! It's not even a matter of money, you simply cannot buy what is not available. You cannot make Moldavite or even predict where to find it - you can hunt for days or weeks and not find a single piece of any size and yet there may be 50 pieces 5 metres away.
Over the last few years as the quantity of 20 gram stones has disappeared into collections around the world it is becoming more common to see 10 and 15 gram specimens begin advertised as HUGE - sadly this is now the case. Within a few years I'm sure we will see 5 gram piece move into the 'huge' category.
Once in a 'blue moon' I get my hands on a piece over 30 grams - it's hard to let them go on the market because I don't know if I'll ever get another piece that size again! It is very tempting to keep them and wait 5 years when the value might be 5 or 10 or even 20 times what it is today, but then what's the point of being in the 'Moldavite Business' if I never sell any thing? I also get the feeling with many pieces that I am merely their intermediary to see them on to their 'real' home.
The value (and cost) of Moldavite increases at an explosive rate once you get passed 30 grams, we have been fortunate to obtain several pieces over 40 grams and even one that is over 60 grams, at a huge cost of course. I'll be putting the 'big girls' in the gallery as I get time to take photos. They just love people admiring them :-)
I also find that some of the bigger pieces give me more of the Moldavite buzz I look for as a healer, but maybe that's because I'm not so sensitive - (or perhaps it's because I've asked them to treat me gently?)