Cultivation: Hash-Oil can be (and is) produced from any kind of Hash, so the cultivation method varies with the origin country.
Production: Hash-Oil is very simple to make: the dried and powdered Buds are soaked in a (preferably Non-Polar) solvent for a couple of weeks, then the solvent is evaporated and what remains is Hash oil.
Color: Extremely dark green to nearly black.
Smell: Highly aromatic and spicy.
Taste: Highly aromatic and spicy, taste however varies considerably with the source material.
Consistency: Hash-Oil (even a highly pure one) is quite thick and hard at room temperature. At body temperature it becomes extremely sticky, when heated it becomes a liquid.
Effect: Very physical and stony high. Most stony and physical high you can find.
Potency: Potent to very potent.
Availability: Quite rare but becomes available from time to time, probably a lot is produced in someone's kitchen.
Various: Nearly always some form of Alcohol is used as solvent. While this works quite well (especially if the source material is already good) there is a lot of Chlorophyll and other inactive substances in the product.
A purer form of Hash-Oil, usually called Honey-Oil, is produced by extracting the material with Petroleum-Ether (or some other non-polar solvent) and separating the water soluble substances from the insolubles. Unfortunately in the origin country usually low quality Dope is used in the production of Oil.
It is also quite easy to be ripped off when buying oil since it's very easy to adulterate.
Cultivation: This Hash is produced from Cannabis plants grown in the Netherlands. Plants are usually cultivated Indoors but there are also small Outdoors and Greenhouse cultivations.
Production: The manufacture method varies with the producer. Most of the Hash is produced thru screening like in Morocco, however there is also a small quantity of hand-rubbed Hash produced using the Afghani method (which of course is much better). However only a very small quantity of the Weed is transformed in Hashish.
Color: Usually quite green, however this varies with the kind of Weed used and the producer.
Smell: Usually quite grass or skunk - like, but depends from the kind of Weed.
Taste: Same as above.
Consistency: A lot of the Dutch Hashish is not pressed correctly (that's an art) and usually beaks apart too easily. However recently the consistency improved, they seem to learn quickly. The above of course doesn't refer to hand-rubbed Hash which is very soft like Afghani. Often the hash is simply the female heads crushed and pressed under huge weights to form a solid lump which very easily powders up.
Effect: The kind of High depends from the strain of Weed which was used, however usually the high is quite active and cerebral.
Potency: Potent to very potent, this stuff is better than any other kind of Hash available to the average user. It even beats most Nepali's and nearly every kind Afghan. (Up to 59% THC)
Availability: Very, very rare outside the Netherlands and surrounding countries. I wouldn't hold your breath waiting for this stuff to appear on the British market.
Various: The quality varies widely however the price is always high. There isn't any standard denomination for the Dutch Hash. High quality powder can come under the name Sensi-Hash which is simply highly compressed THC crystals.