black market tengku eggs

Tengku eggs can be processed into reagents.  Fertilized eggs are even more valuable.
tengku are not known for being the warmest most doting parents but they do love and protect their offspring in their own way, they certainly don't want their offspring turned into mulch in order to make magical items.
Tengku are not a violent race but they will respond violently to anyway they believe is trafficking in stolen eggs.  Tengku are masters of indirect conflict and will not hesitate to strike via proxies if they cannot physically over power their enemies.
Tengku race traitors are rare but not unheard of.  It's one thing for a tengku to con another tengku in a business deal, but it's quite another to coldly traffic dead infants for money.  Tengku that traffic in their races own unfertilized eggs can expect to be banished from their societies.  Tengku that traffic in trading the fertilized eggs of their own people can to be painfully executed by their people if caught.

History & Usage

Everyday use

Tengku eggs reagents can easily be converted into potions and scroll ink related to healing, purification, augmentation, hexing or necromancy with divine magic.  The reagents lend themselves to transmutation, enchantment, conjuration illusion, or necromancy with arcane magic.  
A fertilized tengku egg can typically produce 700 drams of potion ingredients though an egg that is farther along development would end producing roughly 300 drams of potion ingredients and 300 drams of durable reagents and an unfertilized egg can typically produce up to 100 drams of potion ingredient, depending on size and freshness.

Refinement

Everything can be used as reagents, the ground up shell, the yolk, the egg white, and the stunted little chick if present.  A novice alchemist or reagent dealer can preserve the contents for long term storage fairly easily.

Distribution

Trade & Market

The market price for a legal and humanely obtained reagent is normally one silver piece per dram.  Given the illegal and dubious nature of this, the "street value" of this is usually one silver piece per two drams.  So the street value for an fertilized or unfertilized tengku egg is typically 350 silver pieces of 50 silver pieces respectively.

Law & Regulation

Those dealing tengku eggs are likely to face vigilante style justice from the tengku, but most civilized realms in Scarterra recognize tengku as sapient beings and thus trade in tengku eggs in illegal in most human and demi-human lands.  The degree of illegality runs the gamut from a hefty fine to the death penalty.
Kahdisteria only outlawed the trade recently.  The Raykar formally outlawed trade in tengku eggs shortly before establishing Kahdisteria open port in a gesture of goodwill to toengku merchants.

Type

Biomaterial