Coscuez, La Peña Blancas
Muzo Mining District, Colombia
Trapiche emeralds are in a class by themselves and are perhaps the rarest and most memorable of "pattern" gems—certainly the most unusual amongst the big three of emerald, ruby and sapphire. Trapiche is the Spanish word for a "spoked wheel" used to grind sugar cane, which bears a striking resemblance to the pattern in these emeralds. They are typically cut en cabochon to display the beautiful spoke-like star which emanates from a hexagonal center with the areas in between filled with lively green emerald. These rays, which appear like asterisms, are not caused by light reflections from tiny parallel inclusions (as are stars), but from white albite feldspar impurities that happen to form in the same pattern. Gemological examination shows that the trapiche is from white albite feldspar impurities that happen to form in the same pattern and that it is a single crystal and not a twinned specimen as was originally thought. Trapiche emeralds are valued based on a number of factors: saturation and even color, clarity, size and the most important being the definition, completeness and entering of the "rays".
The present offering is a rare suite most of which are consecutive slices from the same crystal: comprising nine oval, plaque-shaped cabochons, each displaying the classic, trapiche effect: the largest, weighing approximately 4.03 carats and measuring 14.10 x 11.96 x 2.2mm; and the smallest, weighing 1.98 carats and measuring 9.9 x 8.4 x 2.5mm. Total weight approximately 23.9 carats (9)