Gold is a chemical element and a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow colour and lustre traditionally considered attractive, which it maintains without oxidising in air or water. Chemically it is one of the least reactive solid chemical elements and therefore occurs often in free elemental or native form, as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, usually with tellurium. Gold resists attacks by individual acids, but it can be dissolved by the Aqua Regia, (nitric and hydrochloric acid), so named because it dissolves gold. Gold is insoluble in nitric acid, which dissolves silver and base metals, a property that has long been used to confirm the presence of gold in items, giving rise to the term the acid test.
Frankincense is tapped from the very scraggy but hardy Boswellia tree by slashing the bark, which is called striping, and allowing the exuded resins to bleed out and harden. These hardened resins are called tears. There are numerous species and varieties of frankincense trees, each producing a slightly different type of resin. Differences in soil and climate create even more diversity of the resin, even within the same species. Frankincense trees are also considered unusual for their ability to grow in environments so unforgiving that they sometimes grow directly out of solid rock. The means of initial attachment to the stone is not known but is accomplished by a bulbous disk-like swelling of the trunk. This disk-like growth at the base of the tree prevents it from being torn away from the rock during the violent storms that frequent the region they grow in. This feature is slight or absent in trees grown in rocky soil or gravel. The tears from these hardy survivors are considered superior for their more fragrant aroma. The trees start producing resin when they are about 8 to 10 years old.[1] Tapping is done 2 to 3 times a year with the final taps producing the best tears due to their higher aromatic terpene, sesquiterpene and diterpene content.
Myrrh is the aromatic oleoresin, (an oleoresin is a natural blend of an essential oil and a resin) of a number of small, thorny tree species of the genus Commiphora, which grow in dry, stony soil. Myrrh resin is a natural gum. When a tree wound penetrates through the bark and into the sapwood, the tree bleeds a resin. Myrrh gum, like frankincense, is such a resin. When people harvest myrrh, they wound the trees repeatedly to bleed them of the gum. Myrrh gum is waxy, and coagulates quickly. After the harvest, the gum becomes hard and glossy. The gum is yellowish, and may be either clear or opaque. It darkens deeply as it ages, and white streaks emerge. Myrrh gum is commonly harvested from the species Commiphora myrrha, which is native to Yemen, Somalia, Eritrea and eastern Ethiopia.
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