Gemstones

For lapis lazuli, the finest colour will be an even, intense blue, lightly dusted with small flecks of golden pyrite. There should be no white calcite veins visible to the naked eye and the pyrite should be small in size.

The best onyx gemstones should have a well-polished and reflective surface and should appear slightly transparent. The gemstone should not have any cracks or scratches on its surface, and the setting around the onyx should be clean and well-made.

When you are shopping for citrine jewellery, colour is the most important value factor: the more vivid and bright the golden hue, the more valuable the citrine. Citrine ranges from a light pastel yellow to dark reddish orange. The best quality citrine has a saturated golden hue with fiery orange flashes inside.

Most gemologists agree that it all comes down to colour when purchasing an emerald. The colour should be evenly distributed and not too dark. Rare emeralds will appear as a deep green-blue, while lighter-coloured gemstones are more common (and therefore, often more reasonably priced).

Look at how the garnet reacts under light—both natural and synthetic—and check for intense, saturated colour. Garnets commonly come in a wide spectrum of reds, but can also be green, pink, blue or even colourless. The price of the piece will likely increase for rare colours like green or blue.

The important thing is to look for clay and mud in most cases. In other cases the crystals form in actual rock, making them more problematic to extract. These crystals are often the best, however.

Observe the color of the crystal. Clear quartz may have small inclusions that look like a smudge in the crystal, but overall the crystal should be colorless and transparent. Inspect the crystal shape. Quartz crystals are generally hexagonal prisms that terminate on each end with a six-sided pyramid.