I've seen a beautiful antique jadeite pendant that I'd like to buy but I've heard that some jades are rated as 'B quality'. What does this mean and is there anything specific I should be looking for?
Tsang Chi Fan replies: Broadly speaking, the quality of jadeite is divided into three groups. Group A are stones which haven't been treated. Group B are stones which have been submerged in strong hydro-sulphuric acid. This treatment loosens the stone's structure and a colourless polymer resin is then injected into the stone to make it look translucent. Group C stones have undergone the same acid treatment, but have also been colour-enhanced (these often look dull and unnatural).
Jadeite comes under the umbrella term of 'jade' and is found in black, purple, lavender, green, and opaque to almost colourless. The best quality, and most expensive, jadeite is brilliant emerald green with fine translucency and clarity.
Although there is no scientific method of testing the age of jadeite, it is possible to check whether the stone has been chemically tampered with. Tests are conducted by the Hong Kong Jewellery & Jade Manufacturers' Association (tel: 2545 0817) and start at $650. For the more expensive pieces, you should always ask the supplier to provide a test certificate before you buy.
So many leaves have fallen off my weeping fig tree (ficus benjamina) that it now looks like a skeleton. How can I make the foliage grow back?
Richard Coumbe replies: There are a few possible reasons why your ficus is shedding so many leaves. Moving it to a new location may have had a detrimental effect on the plant and it may simply need time to settle down again. Perhaps the tree has become 'pot-bound', that is, grown too big for the pot it's planted in? If this is the case, you should replant the tree in a pot that is about a third larger in depth and diameter so it can put out new roots and then recover.