Inclusions (Latin Inclusus –closed-in, surrounded) is an addition in a mineral, for ex. An insect in amber piece. Inclusions aren‘t typical to amber, but any other fossil resin. They can be found not only in the Baltic amber, but also in the Canadian Ciderite, polar Siberian upper chalk Retinites, Alaskan Retinite, French resin, Sicilian Simetite, Austrian Eocene sap and other.

The flora and fauna conserved in amber 50 million year ago that survived to this day and its research help to unveil the climatic and geographical conditions of the time when amber trees grew, excluded amber resin and amber was created. The flora and fauna found in amber is similar to the current one because during millions of years its biggest part evolutionized slightly and the living conditions didn‘t change much.

Inclusions are found in limpid layered (trickled) amber that formed when sap periodically seeped out of the damaged tree parts. They‘re stuck to the liquid sap‘s deeper layer‘s surface and then covered by the new portion of the seeped resin. In the massive and variously colored and patterned amber pieces inclusions are rarely found.

FLORA IN AMBER

Sap of the amber trees seeped out mostly in spring when plant metabolism and growth is the most intense. The flora changed thorns and leaves only during the dry season so only 0.4% of plant inclusions are found. Also, the most of the plants in amber resin were influenced by oxygen, thus didn‘t survive. All plant parts that got into amber were ripped off by storms or damaged by parasites. They‘re usually leaves, thorns, blooms and their parts, more rarely branches and fruit. Sometimes on the surface of amber oak or palm tree prints can be found. Plants with thick, meaty wax-coated leaves that grew during in the areas of long dry periods are found often. Plant species that were pollinated by wind dominate. Plant parts are often found not only in dripped amber, but as well as in other types of amber.

23% of tropical climate plant families are found in amber, cosmopolit ones – 46%, moderate climate – 12%, discontinuous areal – 12%, endemic (typical to a certain area) – 7%. This shows that amber forest grew in tropical conditions and the moderate climate plants were only as intermixtures. They comprise 90% of all floral inclusions in amber.

Cryptogam plants

Those are fungus, liverworts and moss.

Liverworts (Hepaticae) are tiny plants that grew on tree trunks and rocks. They‘re found rarely in amber, so it‘s though that they grew not on amber trees, but on trunks of other trees. The most found species are warmth-loving subtropical climate liverworts.

Moss (Musci) is also very rarely found in amber. All moss found in amber belong to the moderate climate range. Almost no species that grew on tree trunks are found.

Fungus (Fungi) were mostly parasites of the amber trees, but they weren‘t the main reason for sap emission. The trees infected with fungus were already diseased and drying-out so they didn‘t emit sap or emitted little amounts of it. There‘s lots of their remains in amber. Usually himenomicetic-spongiform fungus is found that infests the already weak and damaged, but still growing trees and then timber starts to rot.

Gymnospermous plants

These are coniferous plants (Coniferae) – trees of pine, taxodic and cypress families. Gymnospermous plants are abundant in amber.

Pine is found most often – 15 species. Those are Pinus succinifera, Cembra, Paracembra, Parrya, Balfouriana, Strobus group pines.

From plants belonging to the taxodic family, only sequoia (Sequoia) species is found. Pines and sequoias are typical to moderate and quite humid climate.

Cypress family plants (Thuja, Thujopsis, Biota, Widdringtonia, Libocedrus, Chamaecyparis and others) are found in great numbers in amber and they are typical to warm and quite dry climate of the Northern hemisphere.

Angiospermous plants

Those are the remains of scrub, bush-like palms that grew on the edges of the forest as well as the remains of oak, beech, laurel, bayberry, magnolia, saxifrage, heath.

Angiospermous plant remains are found abundantly in amber and they‘re in good state (mostly leaves or blossoms). Oak predominates in the amber remains. In many amber pieces, especially in the trickled one, quite often tufts of oak inflorescence or their parts are found. This shows that most of the amber was formed in very short time – when the oak trees were blossoming. Warm and dry climate plants are found as well as species of tropical plants. Plants growing on forest edges, fields and wastelands are found in abundance. There are some typical dry warm climate plants such as heath and sub-Alpic field plants.

Microorganisms in amber

Those are bacteria, pollen, lower fungus, algae, spores, cists, eggs of small arthropods.

Bacteria and lower fungus is found in every amber piece. Bacteria and lower fungus isn‘t considered inclusions by some researchers because it‘s thought that they appeared in sap when it got into the forest soil and during its biochemical processes.

Pollen is rare even though there should be lots of, because the blossoming of pines matches with the most intensive sap emission. It is thought that they dissolved in amber influenced by terpenes, because modern pine pollen also disintegrates in a day in turpentine.

There are a lot of spores in amber, but it‘s difficult to identify most of them. Fungus and green moss spores are excluded. In soils amber frequently remains of mycelium that formed in the rotten timber.

Quite often various algae are found in amber timber fibers or in clean amber.  Mostly it‘s green and blue algae. Cists and eggs of arthropods aren‘t found often in amber.

FAUNA IN AMBER

Only small mostly forest insects are found in amber, because larger ones managed to escape. Water, field or wasteland animals got into the sap very rarely. Very few animals that lived in dry areas or during the dry season because sap mostly seeped out in spring when plant metabolism and growth was the most intensive. Insects flying during other seasons didn‘t get into the resin. The quantity and variety of amber inclusions depends on the amount of sap excluded. If there was enough sap to cover the insect – the inclusion survived, if not – then the insects didn‘t stick or disintegrated. Sap had lots of volatile terpenes of unpleasant smell which repelled insects so they got into amber only accidentally – thrown by wind, got stuck while crawling, were covered by running sap on the tree trunk alive, but because of the poisonous substances in terpenes got poisoned and died very quickly.

The sap was very liquid so most part of the insects are very well preserved, even the smallest fragments can be seen – the hair, wing plates. In thick and tenacious sap the insects would have deformed, frayed and stuck together. Most of the inclusions aren‘t rotten as amber is almost air-tight. Only those organisms that had more soft tissue (bugs and larvae) emitted a certain amount of gal and got covered in white opaque layer. Because of oxidation the color of insects didn‘t survive in amber. Inclusions are from all shades of brown to black.

Arthropod fauna in amber

Those are scorpions, pseudo-scorpions, ticks and spiders. They‘re very frequent in amber. Out of scorpion (Scorpionida) order Tityus tribe is found that is typical to current North and Central America.

Spiders (Arachnida) found in amber are mostly tropical or subtropical species that currently live in Southern Africa, India-Malay region, Australia, South America. Forest spiders predominate that live on plants under the bark. Most of them active only at night. Apart from the spiders themselves, traces of their actions are often found in amber – spider webs stuck to tricklets, various tangled timber parts, sucked-out and dried insects.

Initial wingless insects and winged insects

It‘s impossible to name all of them in this review so we‘ll demonstrate only several pictures:

ARTIFICIAL AMBER WITH ARTIFICIAL INCLUSIONS

Sometimes it happens, that dishonest manufacturers offer falsified amber with artificial inclusions. So it‘s advisable to purchase amber only from certified manufacturers who are joined by a international guild and certify their products.

Artificial amber is made out of phenol tar, cellulose (cellulose nitrate), casein, modern plastics (polyester, polystyrene) and the inclusions are clearly too large and inserted into the center. Artificial amber emits the smell of burning plastic instead of the smell of sweetish burning sap aroma like the real amber does.

Here are several artificial amber photos that are offered on the market:

A few tests are done to differentiate artificial amber from the real one:

1. Acetone test

If you drop a droplet of acetone (nail polish) onto the piece you‘re purchasing and the surface becomes sickly – it‘s fake amber, because real amber doesn‘t react to acetone.

2. Smell test

Smell test is the most effective test as natural amber has a specific smell and falsificates don’t have it. Amber smells of sweet and pleasant pine sap. When heated Baltic amber emits a specific subtle pine resin aroma.

3. Rubbing test

When strongly rubbed by hand, natural amber will emit pine smell and the plastic „amber“ is odorless. „Amber“ made of glass is cold, fire and scratch proof.

4. Hot needle test

When a hot needle is stuck into amber a natural pine smell is emitted. Plastic is penetrated by the needle without any breakage and amber tends to be fragile – thus around the hole of the needle cracks will be seen. A disadvantage of this method is that a small stain stays after the burning.

5. Salt and water test

Mix 7-8 spoonfuls of salt with 300 ml of water. In this solution natural amber will float. The disadvantage of method is that you can‘t establish fake polymeric ambers.

6. Fake inserted inclusions
There are plenty of cheap imitations with artificial „inclusions“. The inserted insects (sometimes scorpions, lizards, plants) are much too large and usually look too good to be true.