- Color: Blue Spinel - Shape: Marquise 3x7mm - Quantity: 5 pieces Thank you for viewing. I purchased these to use when making accessories with silver clay, but I haven't been making them for a while, so I'm selling them. These are synthetic stones that can be fired together with silver clay. Please feel free to ask if you have any questions. I may be slow to respond as I am working. Simple packaging will be used. When shipping, I may use recycled packaging. Thank you for your understanding. Although these are unused, there may be some scratches as they have been stored at home. I do not smoke, but I have a cat. Please refrain from purchasing if you are looking for a perfect item.