I’m a fan of crypto currencies. They have the potential to be incredibly disruptive in how we make payments by largely eliminating middlemen that take a big chunk for themselves.

But they’ve had a huge, triple-digit rally year-to-date. And Initial Coin Offerings (ICOs) mimic the kind of rapid mania seen with flipping houses or buying tech stocks one and two decades ago.

Even worse, the charts of the major cryptos have gone parabolic this year. When price movement is that rapid, it’s quick to make easy money. That can create a situation where more potential buyers get in, out of fear of missing out.

But what happens once everyone is in who wants in? Buying demand declines. The price rally stalls. The parabola tends to unwind just as quickly as it started out.

We might not be at the endgame for crypto currencies—yet. But the crackup will come. It already came to the space back in 2011, when the space was largely dominated by Bitcoin.

That wasn’t the only big boom and bust in prices that happened that year. It was also a year when so-called financial professionals were pounding the table on rare earth elements (REEs).

Composed of such rarities as promethium, used for nuclear batteries, or thulium, used for portable x-ray machines, this group of 17 metals saw huge investor interest in a short amount of time. It was easy to see why. Demand was growing out of proportion to supply. And China, which had gradually become the world’s biggest, and lowest-cost producer of the metals, made export cuts in 2009 and 2010 which led to the market imbalance.

But the cure for high prices in any commodity is high prices. Whether through increased production elsewhere, the use of alternative metals, and a global reaction like a World Trade Organization ruling calling out China’s monopolistic practices, sent prices plummeting. That burned investors who bought in to the REE hype on the assumption that the current status quo would never change. It did.

It takes more than imbalances in supply and demand to create big price movements. It takes a lot of speculative capital moving in our out based on fear or greed. This year, we’ve seen growing greed in the crypto space, culminating with many financial professionals pushing towards crypto holdings.

There’s been a vast increase in the number of participants in the space, dwarfing prior years. That’s akin to folks shifting careers to get into housing a little over a decade ago, or folks who quit their jobs to day-trade high-flying tech stocks in the 1990’s. When the growth happens too fast, it’s prone to overcorrect.

Some still see the cryptocurrency space as a surefire road to riches. And while there’s still some value investing early in what could potentially be a new asset class, there are some danger signs. They’re similar to the signs you’d see in the other alternative currency, gold. Even though gold has been used as a currency for thousands of years, it primarily isn’t today. A gold brick is useful as a doorstop, a paperweight, or for its convertibility into cash. It doesn’t do anything or generate revenue.

That’s gold’s biggest criticism—and it’s one that applies to the crpytos as well. But at least with gold, you still have a doorstop or paperweight. Cryptos are digital code that can, and do, get lost in the infinite abyss. Or the keys to unlocking one’s digital wallet can get lost on an old flash drive, just as a gold bar can be stolen.

In short, while cryptocurrencies may be a better alternative to the cash and credit of today, it’s still imperfect. That’s not an impression that one might get from the headline news.

The crypto crackup—its second iteration following the 2011 drop—may be starting. Last week, bitcoin prices tumbled over 10 percent in just a few short trading days, although it’s since recovered.

The cryptocurrency had a fork, splitting between the existing coin and a competing method known as Bitcoin Cash. While Cash briefly surged fourfold in value, it then crashed within the space of just a few hours over the weekend.

That doesn’t sound like the kind of store of value you’d associate with a currency. It’s a speculation. It’s just been an immensely profitable one year-to-date that’s had a few pullbacks—until recently. It may continue for a while. But it will have some big pullbacks. And that’s when you want to start buying.

In short, you haven’t missed the opportunity to buy yet for the long haul—but prices are simply too frothy to seriously buy into the space right now right now. Bitcoin had a huge rally like this in 2011—and shed over 80 percent of its price from that peak. Yes, if you’d bought at the highs then you’d be sitting pretty today. But you could still have done even better waiting for that prior parabolic move to finish its downswing.

Look for an opportunity in the weeks and months ahead to start buying crypto if you haven’t already. Besides Bitcoin, I’m interested in the Ethereum, which I think can be the equivalent of buying silver in this space. The blockchain technology here looks attractive—and the price is much easier to make accumulation possible. For an even less expensive cryptocurrency to buy, there’s also Litecoin.

I wouldn’t look to buy all at once. Rather, regular buys on a monthly basis—like paying a bill or making a retirement account contribution—will allow you to accumulate as long as prices are more reasonable. That’s an approach that’s worked for buying gold as an insurance hedge against the unknown. And while cryptocurrencies likely have a bright future ahead, it’s one where you can do well without risking more than 10 percent of your wealth.

Andrew Packer is a Senior Financial Editor with Newsmax Media. He currently writes the Insider Hotline investment advisory, serves as investment director for the Financial Braintrust, and writes the monthly newsletter Crisis Point Investor.