So if a dealer has to choose between a larger stone and a more vividly colored one—all other factors ... Growth tubes—long hollow tubes often capped with minute mineral crystals—are also common ...

The region produces a variety of garnets (figure 1), sapphire, tourmaline, and zircon. The guidebooks, written in Swahili and showing different types of gem rough found in the area, were distributed ...

Discovered in Brazil in the 80s, these stones are bringing new colour to high jewellery collections In September a ...