The Scottish Gemmological Association

Workshops - Conference 2010

Visual Optics (Alan Hodgkinson) - 2 Sessions

The Visual Optics workshops will be limited to ten participants only.

The participants will have the chance to work singly with a range of gems including diamond, ruby (natural or synthetic), almandine garnet (rhodolite), zircon, peridot, tourmaline, amethyst (or other crystalline quartz), lead glass, CZ, synthetic moissanite, and lithium niobate. Gemstones will be provided, but as some of stones are small, it would be to participants' advantage if they could bring as many larger, facetted examples of the listed gems as possible. The stones may be loose or mounted, provided there is an open back setting, and the setting is reasonable clean.

The workshop will go from first principles to the use of the Birefringence/Dispersion ratio which will be shown to have a fundamental benefit to the user. See the distinction between zircon and lithium niobate below, which most gemmologists identify as zircon when the loupe alone is used.

Crystals and Gemstones (Maria Alferova & Brian Jackson)

The workshop will allow hands on exploration of the relationship between gem crystal habit and features observed in cut gemstones using gemmological tools. Examples of different crystal shapes including oddities such as twinning, distortion, zoning etc. will be available for handling and examination.

'The Orient Express' - Pearls (Vanessa Paterson)

A hands on workshop looking at freshwater, non beaded and beaded cultured pearls, south sea cultured pearls, tahitian cultured pearls and how to separate marine cultured from freshwater, natural pearls, including rare pearls, clam, abalone, conch, and natural freshwater. The workshop will also look at treatments and how to spot them, plus values and where to price pearls and how to grade pearls.

Identifying Colourless Stones in Jewellery (Gwyn Green)

The workshop will put the principles and methods outlined in Gwyn's talk in examining pieces of jewellery set with colourless stones. Participants should have a loupe and a pen torch, if possible, and will examine and identify a comprehensive range of colourless gemstones

'First Thoughts aren't necessarily the Best' (David Callaghan)

A first impression is often a good guide to the question – what is it? However there are pitfalls to be avoided and David’s workshop will highlight the importance of having an open, but questioning, mind when appraising jewellery. Those attending his session are encouraged to bring examples where the first impression has not always been borne out.