Have you inquired at a local college or university that teaches geology and biology? The picture seems to lack any definitive information that would help with identification. An interesting puzzle; good luck.
Here's my guess. Perhaps this sample is Citrine and Amethyst crystals called Ametrine which has a purple and yellow color. Also, let me suggest going to the internet to locate a gem stone dealer that sells to amateur gem stone collectors and to folks that attribute special properties to samples like you have. Such dealers may be able to accurately assess your sample and estimate its value.