The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( TheStreet) -- Silver hit a 30-year high this week. Whenever an asset class -- in this case silver -- experiences a rapid increase in price coupled with the attention of a majority of investors and media, talk of a bubble begins making its way around the numerous outlets investors use to express their feelings with respect to the financial markets. Defining a bubble is a subjective exercise, at best. Asset bubbles inherently vary in the amount of appreciation they experience, the length of time they persist and the underlying reasons they exist in the first place. Some bubbles can continue for years and have very well defined reasoning behind them. Others can last only a few months with the reasoning being without fundamental merit. The only way I have found to define a bubble and come up with any rational target for its expiration is through price action. Fundamentals will never allow you to define a bubble, as they become clouded by emotion during bubble phases. Realistic thinking and rationality is replaced by pervasive greed and unrealistic expectations. The price action during most asset bubbles is surprisingly similar if you filter out the noise by using either a weekly or monthly chart. There are 4 key elements involved: 1. A rapid increase in price that blows away anything that the asset has done in the recent and distant past. 2. Buying that is violent and disorganized. 3. Weekly or monthly price ranges that begin expanding exponentially versus previous bars. 4. A dramatic increase in trading volume. The best way to illustrate these examples is by viewing the charts of past asset bubbles and looking for the similarities. Fortunately, we have had quite a few assets bubbles over the past 10 years that we can use to formulate an opinion on silver. We're going to look at the bubble in the Nasdaq between 1999-2000. The bubble that developed in real estate, expressed through KBH. And the bubble that developed in oil between 2007-2008. We will look at the price action on a monthly basis to filter out a majority of the noise.