As for essential oils that have long shelf lives usually, they are the thicker ones, such as Cedarwood, Sandalwood, Patchouli, Vetiver and a few others. Exception to this thick oil quality will be the essential oil of Rose Otto.
The season for them is generally a short one. Begins in early July and last for 2 to 3 weeks. Black raspberries tend to ripen before most red raspberries varieties expect for the early ripening summer ones.
There is also a purple raspberry which is a cross between the red and black raspberries and a yellow raspberry which is a genetic mutation that occurs in red raspberries. Among these types there are 200 different varieties of raspberries. Archaeological evidence shows that Paleolithic cave dwellers ate raspberries.