Free form Australian Opals are excellent for handmade jewellery as each of them is unique.
There are various calibrated sizes and free form for pairing
There are opal jewellery in 14K gold and 925 silver with gold and rhodium plated.
There are oval,
round, pear and
marquise shape with several standard sizes for clients
Opal triplet grading is depending on the following aspects
Play of colour