Difference Between calibrated tanzanite stone & single stone:
Buying loose gems is harder than picking out jewelry. You aren’t just looking at the Beauty of the gem and its setting and metal, you also have to pay utmost care to the quality of the stone itself – its cutting, facets, calibration etc.
Based on size and cut, there are two categories of tanzanite stones, those that are calibrated and those that aren’t – that is, they are single stones.
The difference is rather straight forward. Calibrated gems are pre-cut into standard sizes and shapes, with a regularized faceting and base to fit into ready-made jewelry mounts. Though various shapes exist, the most common calibrated tanzanite gems are round and oval.
Round calibration is preferred as it tends to have facets close together, giving a rich color intensity to the stone as all the refracted light gets focused. It is also ideal for setting in jewelry that requires clustered gems or paved gem surfaces. The fact that these are used in clusters makes the quality of each stone in terms of inclusions take a backseat – the color and size uniformity is what must be assured. This is because individual flaws may not show, but as a whole consistency is preferred. Calibrated round gems are usually not available at sizes larger than 8.00 mm.
Oval calibrations also have a similar reference point for their popularity, adding a slightly elongated dimension to the fore mentioned round cut. This cut is the most popular worldwide, especially for studs and tennis bracelets.
Certain specific settings require straight edged shapes – square, emerald and princess to name a few. Besides these, people who want a unique piece go for pear, trillion, cushion, heart and marquise as well. Usually more complex the shape, the smaller the stone tends to be because of increased wastage; prices too increase with complexity in cut.
Another trend in tandem with calibrated gems is that of cabochons, a stone that is shaped and polished as opposed to faceted. Though its sparkle decreases the color is unmatched.
As opposed to a calibrated tanzanite stone, a single tanzanite stone is one where you can choose your own cut. A calibrated stone is factory cut, and it reduces labor and hence costs. Single stones are custom made, hence unless your piece of customized jewelry absolutely requires it, the economical idea would be to stick to standard sizes.
On the other hand single stones are often chosen by buyers to optimize the size of a rough stone, in order to make a piece of statement jewelry. Look at the purchase of calibrated or single tanzanite in terms of your use – for example if the custom made earring or pendant doesn’t justify the cost of getting the stone cut to size, then you should probably avoid it. Not to mention in today’s market, a great variety of calibrated shapes and sizes exist. If shape is not what worries you in a calibrated stone and it’s the size you want to change, remember that jewelers are usually skilled to modify the setting according to the gem.