This gorgeous rare item is crafted in solid 18k solid yellow gold and solid Australian Lightning ridge semi black semicrystal round large 9.5-9.95Ct Opal. the opal is approx 12mm round and 9.5-9.95Ct and is solid natural untreated Australian Lightning ridge semi black translucent semicrystal Opal - not doublet and not triplet not boulder but solid Australian opal. it has smooth polish and has no cracks no crazing - please see last photo against light. if you ever wish to check opal for crazing/cracks it is easy - just look at it against the light and you will see if there are any - it will look as dark brown/black lines. I hand pick and check every single item and I do not accept any with crazing. highly polished surface!. also the very last photo shows the light which was used to take video. the other photos and a photo on a green leaf in day light no Sun. as with most opals the colors are stronger on the Sun and direct indoor light and not so in a dark/low light. the item as in new condition! it is an enchancer and can be attached to any beaded necklace or any chain - it opens as a clasp /please see photos. there are also diamonds - 1 baguette 3x2.6mm, 2 bezel round approx 1.8mm and one prong set aprox 1.5mm! super rare item made in antique Victorian style. fully tested and hallmarked for solid yellow 18k gold. excellent condition! comes in a jewelry case! can be gifted immediately! last photo shows it on a 16? blue flash moonstone necklace - if you wish to have it please let me know and I will include it with the pendant. the moonstone necklace is not antique and it came separate but it looks good together. the moonstone beads are approx 4.2mm each. I also have opal round bead necklace for sale and it will match well too. smoke free environment and fast USA priority insured shipping! fast priority international shipping - please choose at the checkout! thank you! An interesting thought - it is well known fact that opal round beads are very hard to carve with a lots of waste of precious material. for this reason in our days no one really makes Australian opal round beads any more. all of the Australian opal round beads necklaces are very rare to find for sale today and they all vintage or antique. especially hard to find such a large size of the bead as 12mm! I would say almost impossible to find fully round 12mm size! . I have also a few round beads opal necklaces for sale. please see them in my shop. thank you