Ethereum-based prediction markets platform Gnosis, which is part of New York City's ConsenSys studio, has begun the countdown to a much anticipated token sale.

The sale of Gnosis tokens will commence on 24 April and it is capped at $12.5m. Some 10 million Gnosis tokens (GNO) will be created and a percentage of them will be distributed through the token launch. Gnosis is choosing a modified Dutch auction, in which the token price starts relatively high (about $30) and decreases over the course of the sale.

The auction ends when either the sale cap is reached, or the fixed supply of GNO tokens is exhausted. The exchange rate of the block at which the sale terminates becomes the auction price for all participants.

Martin Köppelmann, co-founder, Gnosis said it will use a smart contract so everybody can see the decrease at each block. "It's predictable. Every 50 seconds the price will go down a little bit. Let's say on the first day Gnosis tokens cost $30 and the next day $25 and next day $23. It's not linear, it's curved. The starting price will be relatively high but it will go down rapidly in the beginning and then it will slow down.

"In the end everyone will get the same price. If you put in the money early then you are basically expressing you are willing to pay a high price per token, but in the end you will get the same price as the last person that gets in, basically the lowest price."

Some ICOs offer special bonuses to early investors to mitigate the dilution of their share as the sale progresses. They try and counter any disadvantage derived from putting in money early with the early bonuses. "We think that's all a little bit messy. With our concept, the moment you go in you know your share you get can only go up."

In addition to the news about the token sale, Gnosis is introducing some new apps, such as "Hunchgame". "It's about gossip," said Köppelmann. "So, will George Clooney and his wife get divorced? People can make hunches about things and it's to show the wide range of applications – not all just financial."

Another interesting Gnosis app is called "Price Discovery" and this can be used to establish what the market thinks can be paid for expensive works of art that are auctioned off in places like Christies, for example. "Auction houses give guarantees; they say they will sell something for at least $15m and if they in sell it in the end for only $12 then they have to give out $3m. It's important for them to get the forecast right, so why not make a market for those things."

So is there a market to predict how the Gnosis sale will go? "We have this running; this is live right now," added Köppelmann. "You can make predictions on the Gnosis token sale."