The Gem-A student kit is the prescribed collection of gemmological testing instruments assembled for candidates enrolled in the Gemmological Association of Great Britain's Foundation and Diploma programmes. Rather than leaving instrument selection to individual discretion, Gem-A specifies minimum standards for each tool, ensuring that all students — whether studying in London, Hong Kong, or through a distance-learning pathway — work with equipment capable of producing reliable, examination-grade results. The kit represents a meaningful financial commitment at the outset of gemmological study, but it constitutes the professional core toolkit that a working gemmologist will continue to use well beyond the classroom.

Instruments Included

The kit is built around the instruments required to perform systematic gem identification by conventional gemmological methods. The principal items are:

• 10× loupe — a corrected, achromatic and aplanatic hand lens used for surface and inclusion examination. Gem-A specifies a triplet-corrected loupe to minimise chromatic and spherical aberration at the edges of the field.
• Dichroscope — a calcite-prism instrument (the calcite dichroscope, as distinct from the polarising-filter type) used to observe pleochroism in transparent coloured stones. Detection of pleochroism is a primary step in narrowing identification to uniaxial or biaxial species.
• Chelsea colour filter — a didymium-and-copper-oxide filter that transmits only deep red and yellow-green wavelengths, historically used to separate Colombian emeralds from simulants and to assist in identifying certain synthetic stones and treated materials.
• Refractometer — the single most important instrument in conventional gemmology, measuring the refractive index (RI) of a polished facet via total internal reflection. Gem-A students use a standard gemstone refractometer with a sodium-equivalent light source (typically a monochromatic yellow filter or LED), capable of reading the range approximately 1.40–1.81.
• Polariscope — a pair of polarising filters in crossed or parallel orientation, used to determine whether a stone is singly refractive (isotropic) or doubly refractive (anisotropic), and to detect anomalous double refraction, strain, or assembled stones.
• Spectroscope — either a diffraction-grating or prism-based instrument used to observe absorption spectra in the visible range, aiding identification of chromophores (e.g., the 693 nm doublet of ruby, the 415 nm band of Cape-series diamonds, the 450 nm band of blue synthetic spinel).
• Tweezers and stone holder — locking or self-closing tweezers appropriate for manipulating loose stones safely during testing.
• Refractive index liquid — a contact liquid of known RI (typically 1.81) applied between the stone's facet and the refractometer's hemicylinder to ensure optical contact.

Some versions of the kit also include a specific gravity (SG) set — a fine balance or hydrostatic weighing apparatus — and a ultraviolet lamp (longwave and shortwave), though these may be supplied separately depending on the programme pathway and year of enrolment.

Role in the Gem-A Curriculum

The Foundation Certificate in Gemmology introduces students to each instrument methodically, building from loupe observation and polariscope testing through to refractometry and spectroscopy. The Gem-A Fellowship Diploma (FGA) extends practical work to include systematic species identification across a broad range of natural, synthetic, and treated stones. Practical examinations at both levels require candidates to identify unknown stones using only the instruments in the kit, without access to advanced laboratory equipment such as EDXRF spectrometers or laser ablation ICP-MS. This constraint is deliberate: it trains the gemmologist to extract maximum diagnostic information from portable, affordable instruments — the same instruments that are practical in a trade environment, at an auction preview, or in the field.

Instrument Standards and Sourcing

Gem-A does not mandate a single manufacturer for most instruments, but it does specify performance thresholds. The refractometer, for instance, must be capable of accurate readings across the full gemstone RI range and must be compatible with standard RI liquids. Commonly encountered brands in student kits include Krüss and Rayner for refractometers, and various suppliers for loupes and dichroscopes. Gem-A itself retails a curated kit through its online shop, which guarantees compliance with examination requirements — a practical consideration for students who might otherwise purchase instruments that fall short of the specified standard.

Investment and Long-Term Value

The cost of a complete Gem-A student kit is substantial relative to other study materials, but the instruments are durable and professionally serviceable. A quality refractometer and calcite dichroscope, properly maintained, will remain accurate for decades. Many gemmologists who qualified through Gem-A continue to use their original student instruments throughout their careers, supplementing them with electronic or spectroscopic tools as their practice develops. The kit therefore functions not merely as examination apparatus but as the foundation of a professional instrument collection.