If the dome is oriented in between these two directions, an ‘off-center’ star will be visible, offset away from the high point of the dome. The inclusions can alternatively produce a “cat’s eye” effect if the ‘face-up’ direction of the cabochon’s dome is oriented perpendicular to the crystal’s c-axis rather than parallel to it. Misshapen stars or 12-rayed stars may also form as a result of twinning. Occasionally, twelve-rayed stars are found, typically because two different sets of inclusions are found within the same stone, such as a combination of fine needles of rutile with small platelets of hematite the first results in a whitish star and the second results in a golden-colored star.ĭuring crystallisation, the two types of inclusions become preferentially oriented in different directions within the crystal, thereby forming two six-rayed stars that are superimposed upon each other to form a twelve-rayed star. The stones are cut en cabochon, typically with the center of the star near the top of the dome.
The inclusion is often the mineral rutile, a mineral composed primarily of titanium dioxide.
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