Inclusions
Inclusions
A general name for any small visible foreign matter such as gas, liquid, glass, or mineral enclosed within a gemstone or rock, which is a growth phenomena. Fracture or cleavage in a gemstone are not classed as inclusions. The nature of inclusions are used to indicate the origin of a stone. Inclusions are very helpful in distinguishing synthetic stones from their counterparts. Inclusions are divided into two categories: (I) primary inclusions and (II) secondary inclusions. Inclusions may result in three formations: (a) pre-temporary inclusions, pre-existing inclusions, or photogenetic inclusions, (b) contemporary inclusions, or syngenetic inclusions and (c) post-temporary inclusions, post-formed inclusions, or epigenetic inclusions. Some types of inclusions type are: feather, silk, horsetail, veil, fused or treacle, negative crystal, halo, fingerprint, dendrite, centipede, pleochroic halo, zircon halo, two-phase, three-phase, etc. Inclusions are divided in four shapes: (a) solid inclusions, (b) internal cavities, (c) cracks or fissures, and (d) growths.