Amber is fossilized tree resin. This organic material offers a glimpse into prehistoric ecosystems, preserving traces of life from millions of years ago. Unlike true minerals, amber forms through a biological process from the resin of ancient trees, making it a distinctive natural treasure.
Formation and Origin
Amber begins as a sticky resin exuded by ancient trees, primarily conifers like the extinct Pinus succinifera for Baltic amber, or Hymenaea protera for Dominican amber. This resin serves as a protective mechanism, sealing wounds in the tree’s bark caused by insects or physical damage. The resin’s antiseptic properties also guard against disease and fungal infections. For this resin to become amber, it must be resistant to decay and buried quickly in an oxygen-free environment, such as sediment in coastal regions or river deltas.
Over millions of years, under significant pressure and temperature from overlying sediments, the resin undergoes a process called polymerization. This chemical transformation causes small molecules within the resin to chemically combine, forming larger, more stable molecular structures. Initially, the resin hardens into copal, a subfossil resin, before further sustained heat and pressure drive off volatile compounds, leading to the formation of inert amber. Most amber found today ranges from approximately 30 to 90 million years old, though some older samples date back as far as 320 million years.
Distinctive Properties
Amber exhibits a wide spectrum of colors, ranging from yellow, orange, and brown, often translucent to opaque. Rarer hues include red, green, blue, and even white. The degree of transparency and specific color often depends on the presence and distribution of microscopic air bubbles trapped within the resin during its formation. A higher concentration of these minute bubbles can result in a cloudier or milky white appearance, sometimes referred to as “bony amber.”
Compared to true minerals, amber is relatively soft, typically registering between 2.0 and 2.5 on the Mohs hardness scale, similar to a fingernail. It is also notably lightweight, with a specific gravity between 1.05 and 1.10, allowing it to float in saltwater. Amber’s ability to preserve inclusions, such as ancient insects, plant matter, or even small vertebrates, which became trapped in the sticky resin, provides insights into prehistoric life and environments, acting as natural time capsules for scientific study.
Global Distribution and Varieties
Amber deposits are found across the globe, with significant occurrences in both the Old and New Worlds. The Baltic Sea region, including Lithuania, Latvia, Poland, and Russia’s Kaliningrad Oblast, is the most prominent source, accounting for approximately 80-90% of the world’s extractable amber. This Baltic amber, known as succinite, is typically around 40 to 60 million years old and often characterized by its high succinic acid content. Its colors commonly range from yellow to brown, though white, blue, and green variations exist.
Another notable source is the Dominican Republic, where amber deposits are generally younger, dating back about 15 to 25 million years. Dominican amber is known for its exceptional transparency and frequent well-preserved fossil inclusions compared to Baltic amber. This region is also known for its rare blue and green amber, colors resulting from unique optical properties rather than inherent pigments. Other significant amber localities include Myanmar (Burmite), Mexico (Chiapas amber), and various sites across Europe, Asia, and the Americas.