I've had a request for FR jewellery - basically using the FR elemental clan symbols in pendants such as these:

I have no knowledge or experience in this sort of thing - all the current designs I'm doing are made by me from scratch with a font available for commercial use (yay for uni making us pay for a stock account lol). What's the stance on this? Will I get hunted down by FR for using their symbols? I've seen people selling artwork featuring dragons etc - will I have to sell them for FR currency or is real life cash ok too since they are commissions? xD
The person who has asked me says I can make and sell 6 of any design no problem - I really hate art thieves so won't touch FR intellectual property if it's not right... :/ They can't remember where they got the number 6 from either which isn't much help but they are sure that FR are cool with it >_>